Methods, systems and apparatuses for torsional stabilization

ABSTRACT

Methods, systems and apparatuses are provided for torsionally stabilizing a spinal motion segment. One or more implants are placed between two vertebrae to provide torsional stabilization. In particular, one or more implants may be fixed between a superior vertebral body, such as at the spinous process, and an inferior vertebral body. The implants may be connected to the superior vertebral body using a fixation device such as a turnbuckle, an outrigger, a thimble, an endobutton, a suture plug or combinations thereof. The implant may also be connected to the inferior vertebral body using various types of hardware, including staples, screws and anchors. The implant may be kept in tension to provide torsional stabilization and may be comprised of one or more sutures. A multi-functional instrument having one or more arms having holes can be used to clamp onto the superior vertebral body and guide one or more implants to various locations for fixation in accordance with the methods described herein.

The present application claims priority under 35 U.S.C. §119(e) to U.S.Provisional Patent Application Ser. No. 60/980,534, entitled“Torsionally Resistive Spinal Implants and Methods,” filed Oct. 17,2007, U.S. Provisional Patent Application Ser. No. 61/034,115, entitled“Torsionally Resistive Spinal Implants and Methods,” filed Mar. 5, 2008,and U.S. Provisional Patent Application Ser. No. 61/058,885, entitled“Torsionally Resistive Spinal Implants and Methods,” filed Jun. 4, 2008.The entire disclosures of all the priority applications are herebyexpressly incorporated by reference in their entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present application relates to methods, systems and apparatuses totorsionally stabilize a spinal motion segment.

2. Description of the Related Art

In many patients, an early finding associated with back pain is aweakening or disruption of the annulus. Patients in this state may thenbe treated with either micro- or open discectomy to remove any fragmentsassociated with pain. Typically, these patients do well in the shortterm, but eventually have degeneration leading to axial (back or neck)pain, sometimes also in the presence of radicular pain, radicularweakness or a loss of sensation radicularly.

In patients with low back pain generally, including those withoutdisruption of the annulus, there is known to be excessive axialrotation, as recently shown by Haughton et al., Measuring the AxialRotation of Lumbar Vertebrae in Vivo with MR, Am J Neuroradiol 23:1110-1116, August 2002. Also, scoliosis patients are known to havechanges in the multifidus, which is a significant contributor to spinalstabilization and is a significant generator of axial rotation. In boththe population of patients with low back pain, and in scoliosispatients, there may be benefit to a device that increases the stabilityof the segment(s).

Mechanically, the annulus is a significant structure. In the lumbarspine, the annulus is reported to be on the order of 10 mm thick in theanterior half of the body, but perhaps less than 5 mm posteriorly. Assuch, it can represent 40 to 60% of the overall area of the endplate. Itis known to resist compression, tension, flexion/extension, lateralbending and axial rotation.

With weakening or disruption of the annulus, mechanical changes in theannulus' behavior are expected. It is of value to consider themechanical impact of annular defects in the different loadingdirections.

The compression and tension behavior of the annulus is determined by thematerial properties of the annulus and the annulus' cross-sectionalarea. The size of the annular defect is a relatively small percentage ofthe overall annulus. For example, a 10 mm diameter defect in an annulusonly represents 8% of the overall annular area. As such, an annulardefect has a modest impact on the area, and therefore, the compressiveand tensile load carrying capacity of the motion segment.

In flexion/extension or lateral bending motions, the structural behaviorof the motion segment is related to the moment of inertia of theannulus. Like tension/compression, the annulus is a significantcontributor, and the effect of a defect has a relatively modest impact.Calculations show that an annular defect reduces the moment of inertiaof the annulus by only 10%.

In torsion, the structural behavior of the motion segment is related tothe polar moment of inertia of the annulus. Using an approximation of ahollow circular cylinder for the annulus, the impact of a hole in theannulus reduces the polar moment of inertia on the order of 90%, andgreatly influences the torsional stiffness of the spine. It is thereforedesirable to provide systems, methods and apparatuses that mayeffectively help stiffen motion segment(s) torsionally.

SUMMARY OF THE INVENTION

The present application relates to methods, systems and apparatuses forproviding torsional stabilization of a spinal motion segment. Morespecifically, these methods, systems and apparatuses are related tostabilizing the spine torsionally by placing an implant between adjacentvertebral bodies. In some embodiments, one or more implants are orientedin a plane generally aligned with the disc space, so as to stiffen amotion segment torsionally. The stabilizing implant may comprise asingle entity or two or more pieces.

Methods described permit the surgeon to install hardware at two, orpreferably three locations, generally aligned with the disc space, andto pass one or more implants between the locations, so as to treat asingle spinal level. A single spinal level is defined as a disc space,the vertebral body above the disc space and the vertebral body below thedisc space. Preferred fixation on the superior vertebral body is to thespinous process and is the sole point of fixation on the superiorvertebral body. Preferred fixation on the inferior vertebral body isbilateral, though fixation could be unilateral.

Systems for providing torsional stabilization to a spine are provided.In one embodiment, a system comprises at least one implant configured toextend between a superior vertebral body and an inferior vertebral bodyoriented in a plane generally aligned with the disc space to providetorsional stiffness to the spine. A first fixation device is configuredto fix the one or more implants to the inferior vertebral body. A secondfixation device is configured to fix the one or more implants to thespinous process of the superior vertebral body. To assist with aligningthe first and second fixation devices to desired locations, the systemalso includes a clamping mechanism configured to attach to the spinousprocess of the superior vertebral body. The clamping mechanism comprisesone or more arms, said one or more harms having one or more holesoriented to align with a location desirable for attaching the first andsecond fixation devices.

Methods for providing torsional stabilization to a spine are provided.In one embodiment, a surgical instrument is clamped to the spinousprocess, wherein the surgical instrument comprises a clamping mechanismfor attachment to the spinous process and one or more arms, each armhaving one or more alignment holes oriented to align with a locationdesirable for attaching one or more fixation devices. A hole may then becreated in the spinous process of the superior vertebral body through afirst alignment hole of the surgical instrument aligned with a desiredlocation on the spinous process of the superior vertebral body. Astabilizing implant may then be inserted through a second alignment holealigned to a desired location on an inferior vertebral body and a firstportion of the stabilizing implant fixed to a desired location of theinferior vertebral body. The stabilizing implant may then be capturedthrough the created hole in the spinous process and pulled towards thespinous process where it may be attached.

In another embodiment, a method for providing torsional stabilization toa spine comprises extending an implant in tension between a firstvertebral body and a second vertebral body, the implant being attachedto a fixation device engaged to the spinous process of the secondvertebral body and extending laterally outwardly to attach to a locationon the first vertebral body.

In another embodiment, a method for providing torsional stabilization toa spine comprises creating a hole through the spinous process of asuperior vertebral body. A suture may then be attached to a firstlocation on an inferior vertebral body. The suture may be extended fromthe inferior vertebral body to the spinous process of the superiorvertebral body along a plane generally aligned with the disc space andsecured to the spinous process of the superior vertebral body via anendobutton secured to the hole in the spinous process, wherein thesuture is placed in tension to provide torsional stabilization.

Novel instruments are provided that enable the surgeon to prepare two ormore locations for fixation, to pass one or more stabilizing implantsbetween the different locations, to tighten the stabilizing implantsand/or to fix the stabilizing implants to various hardware. In oneembodiment, a surgical instrument is provided for delivering hardware tothe spine comprising a clamping mechanism configured to be inserted intoa patient and attached to the spinous process of a first vertebral bodyand at least one arm extending laterally outwardly from the clampingmechanism and configured to be positioned outside of the patient. The atleast one arm has at least one hole oriented to align with a location oneither the spinous process of the first vertebral body or a laterallocation on a second vertebral body, the at least one hole beingconfigured to guide an instrument to either the spinous process or tothe lateral location on the second vertebral body.

Apparatuses are provided comprising a suture anchor loaded with one ormore sutures. The suture anchor comprises a threaded shaft and a suturehead connected to the threaded shaft. The threaded shaft comprises aneyelet hole and a rounded post, wherein the eyelet hole transitionssmoothly into the rounded post, and wherein one or more sutures loadedto the suture anchor make contact with the suture anchor only via therounded post.

Various other systems, methods and apparatuses are contemplated anddiscussed below. While the systems, methods and apparatuses aredescribed with respect to torsional stabilization of the spine, many ofthe novel embodiments herein can be used for the stabilization of otherareas of the body, and may be used for other applications, includingnon-spinal applications.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a sagittal (side) view of the lumbar spine.

FIG. 2 shows a top view of a lumbar vertebral body.

FIG. 3 shows a sagittal (side) view of the cervical spine.

FIG. 4 shows a top view of a cervical vertebral body.

FIG. 5 shows an implant having a rounded cross-section according to oneembodiment.

FIG. 6 shows an implant having a rectangular cross-section according toone embodiment.

FIG. 7A shows a tubular implant according to one embodiment.

FIG. 7B shows the effect of a compliant tubular implant when passingaround a piece of bone.

FIG. 8 shows a filled tubular implant according to one embodiment.

FIG. 9A shows a staple which can function as an anchor according to oneembodiment.

FIG. 9B shows a staple assembled to an implant according to oneembodiment.

FIG. 10 shows a front view of an anchor including a bone anchoringportion and an implant receiving portion according to one embodiment.

FIG. 11 shows an exploded front view of an anchor including a boneanchoring component and an implant attachment post according to oneembodiment.

FIG. 12A shows a front view of an offset anchor according to oneembodiment.

FIG. 12B shows a side view of the offset anchor of FIG. 12A.

FIG. 13 shows a posterior (rear) view of a lumbar vertebral spine.

FIG. 14A shows a posterior (rear) view of a lumbar vertebral spine withan implant and anchors, where the implant is attached to the superiorvertebral body via a loop according to one embodiment.

FIG. 14B shows a sagittal (side) view of the system of anchors andimplant of FIG. 14A.

FIG. 15A shows an exploded front view of a turnbuckle.

FIG. 15B shows a right side view of the turnbuckle of FIG. 15A.

FIG. 15C shows an assembled bottom section view of the turnbuckle ofFIG. 15A.

FIG. 16 shows a posterior (rear) view of a lumbar vertebral spine withtwo implants, two anchors applied, wherein the implants are attached tothe spinous process via a turnbuckle according to one embodiment.

FIG. 17A shows a front exploded view of an alternative embodiment of anoutrigger.

FIG. 17B shows a top exploded view of the outrigger of FIG. 17A.

FIG. 17C shows a side view of the outrigger of FIG. 17A.

FIG. 18A shows a clamp used to fix an implant according to oneembodiment.

FIG. 18B shows a section view of an assembly of an implant, hardware andclamp according to one embodiment.

FIG. 19 shows a view of a crimping instrument used to fix the clamp toan implant according to one embodiment.

FIG. 20A shows an alternative clamp that can be used to fix an implant.

FIG. 20B shows a section view of an assembly of an implant, hardware andan alternative clamp according to one embodiment.

FIG. 21 shows a posterior (rear) view of a lumbar vertebral spine havingtwo implants attached to the spinous process via an outrigger accordingto one embodiment.

FIG. 22 shows a posterior (rear) view of a lumbar vertebral spine withone implant attached to the spinous process via an outrigger accordingto one embodiment.

FIG. 23A shows a front view of an outrigger.

FIG. 23B shows a side view of the outrigger in FIG. 23A.

FIG. 24A shows a front view of an alternative outrigger.

FIG. 24B shows a side view of the alternative outrigger in FIG. 24B.

FIG. 25A shows a front view of an alternative spinous process anchoraccording to one embodiment.

FIG. 25B shows a side view of the alternative spinous process anchor ofFIG. 25A

FIG. 26A shows a front view of an alternative spinous process anchoraccording to one embodiment.

FIG. 26B shows a side view of the alternative spinous process anchor ofFIG. 26A.

FIG. 27 shows an alternative clamp according to one embodiment.

FIG. 28A shows a front view of a thimble.

FIG. 28B shows a side view of the thimble of FIG. 28A.

FIG. 29 shows a top view of a multi-functional surgical instrumentaccording to one embodiment.

FIG. 30 shows an alternate top view of the multi-functional surgicalinstrument of FIG. 29 attached to a lumbar spine.

FIG. 31A shows one embodiment of a front section view of amulti-functional surgical instrument, with the movable arm removed forpurposes of clarity, according to one embodiment.

FIG. 31B shows a second embodiment of a front section view of amulti-functional surgical instrument, with the movable arm removed forpurposes of clarity.

FIG. 31C shows a third embodiment of a front section view of amulti-functional surgical instrument, with the movable arm removed forpurposes of clarity.

FIG. 32A shows an oblique view of a multi-functional surgical instrumentaccording to one embodiment.

FIG. 32B shows an alternative top view of the multi-functional surgicalinstrument of FIG. 32A.

FIG. 32C shows an alternative multi-functional surgical instrumentaccording to one embodiment.

FIG. 32D shows a side view of the multi-functional surgical instrumentof FIG. 32C.

FIG. 33 shows a dilator.

FIG. 34 shows a cannula.

FIG. 35A shows an oblique view of a tamp.

FIG. 35B shows an end view of the tamp of FIG. 35A.

FIG. 36 shows a hooker.

FIG. 37 shows a portion of a grabber.

FIG. 38 shows a portion of a puller.

FIG. 39 shows an oblique view of a kerrison-type rongeur configured as agrabber.

FIG. 40A shows a side view of an inserter.

FIG. 40B shows a top view of an inserter.

FIG. 40C shows a front view of an inserter.

FIG. 41A shows a side view of an alternative inserter.

FIG. 41B shows a top view of the alternative inserter of FIG. 41A.

FIG. 41C shows a front view of the alternative inserter of FIG. 41A.

FIG. 42 shows a front view of an alternative hooker.

FIG. 43A shows a front section view of a combination tamp/insertercannula.

FIG. 43B shows a top section view of the combination tamp/insertercannula of FIG. 43A.

FIG. 43C shows a side view of the combination tamp/inserter cannula ofFIG. 43A.

FIG. 44 shows a suture anchor according to one embodiment.

FIG. 45A shows a side view of an anchor driver according to oneembodiment.

FIG. 45B shows a cross-sectional top view of the tip of the anchordriver of FIG. 45A.

FIG. 45C shows an exploded side view of the tip of the anchor driver ofFIG. 45A.

FIG. 46A shows a side view of an endobutton according to one embodiment

FIG. 46B shows a front view of an alternative embodiment of anendobutton according to one embodiment.

FIG. 47A-J show the illustrated steps of one embodiment of a surgicalmethod using a multi-functional surgical tool and an endobutton.

FIG. 48A shows a side view of a measuring instrument assembly accordingto one embodiment.

FIG. 48B shows a front view of the measuring instrument assembly in FIG.48A.

FIG. 49A shows a measurement instrument frame according to oneembodiment.

FIG. 49B shows a measuring filament according to one embodiment.

FIG. 50 shows an anchor assembled to a stabilizing implant with suturesaccording to one embodiment.

FIG. 51 shows a stabilizing implant with a hole assembled with suturesaccording to one embodiment.

FIG. 52 is a side view of a suture anchor according to one embodiment.

FIG. 53 is a cross-sectional top view of the suture anchor of FIG. 52.

FIG. 54 is a top view of the suture anchor and collar of FIG. 52.

FIG. 55 is a side view of a suture anchor inserter according to oneembodiment.

FIG. 56 is a cross-sectional top view of the suture anchor inserter ofFIG. 55.

FIG. 57 is a side view of a suture anchor according to one embodiment.

FIG. 58 is a cross-sectional side view of the suture anchor of FIG. 57.

FIG. 59 is a top view of the suture anchor of FIG. 57.

FIG. 60 is a side view of a suture plug according to one embodiment.

FIG. 61 is a top view of the suture anchor of FIG. 60.

FIG. 62 is a bottom view of the suture anchor of FIG. 60.

FIG. 63 is a cross-sectional view of the side of the suture plug of FIG.60.

FIG. 64A shows a side view of a suture anchor and suture plug using asingle suture according to one embodiment.

FIG. 64B shows a top view of the suture anchor and suture plug of FIG.64A

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Methods, systems and apparatuses are provided in certain embodiments ofthe present application to selectively stabilize the spine torsionallyby placing one or more implants between adjacent vertebral bodiesgenerally aligned with the disc space, so as to stiffen a motion segmenttorsionally One procedure of the present application permits the surgeonto install hardware at two or preferably three locations alignedgenerally with the disc space as fixation devices, and to pass one ormore implants between the locations, so as to treat a single spinallevel. Novel instruments enable the surgeon to prepare locations forfixation, to pass one or more stabilizing implants between locations, totighten the stabilizing implants and to fix the stabilizing implants tohardware.

FIG. 1 shows a sagittal view of the lumbar spine. The presentapplication involves treatment of one or more spinal levels to providetorsional stability. A single spinal level is composed of a disc 11targeted for treatment, a superior vertebral body 12, and an inferiorvertebral body 13.

To provide torsional stabilization without significantly impacting theflexion/extension or lateral bending motion of spinal segments (whichmay be referred to as “selective” torsional stabilization), thelocations to fix the implants preferably lie generally in a planeperpendicular to the torsional axis of rotation 14 of the disc 11. Thetorsional axis of rotation 14 is aligned with the long axis of thespine. Any plane generally perpendicular to the torsional axis ofrotation 14 is defined as being aligned with the disc space. Onegenerally preferred plane 15 shown in FIG. 1 passes through the spinousprocess 16 of the superior vertebral body 12, and the mamillary process17 of the inferior vertebral body 13. An alternative plane 18 passesthrough the pedicle 19 of the inferior vertebral body 13 but does notpass through any part of the superior vertebral body 12. To provideselective torsional stabilization in the alternative plane 18, afixation device, such as an anchor, may be attached to the spinousprocess 16 of the superior vertebral body 12 and one or more implantsmay be fixed inferior to the spinous process 16.

FIG. 2 shows a top view of a lumbar vertebral body 21. In this view, itis possible to identify the spinous process 22, the mamillary processes23 and 24 and the pedicles 25 and 26. It can be seen in this view thatan implant passing generally between the mamillary processes 23 and 24to the spinous process would pass adjacent to the facets 27 and 28.

FIG. 3 shows a sagittal view of the cervical spine. As shown, a singlespinal level is composed of the disc targeted for treatment 31, thesuperior vertebral body 32, and the inferior vertebral body 33.

In the cervical spine, the torsional axis of rotation 34 of the disc 31is shown. The torsional axis 34 is aligned with the long axis of thespine. Any plane generally perpendicular to the torsional axis ofrotation is defined as being aligned with the disc space. One generallypreferred plane 35 passes through the spinous process 36 of the superiorvertebral body 32 and the lateral aspect 37 of the superior articularprocess of the inferior vertebral body 33.

It is recognized that due to anatomical and surgical variation, it isunlikely that all points of fixation will lie precisely within a planeperpendicular to the torsional axis 14 and 34 of the targeted disc 11and 31. However, trigonometry shows that any plane within +/−17.5degrees of perpendicularity with the torsional axis of rotation 14 and34 will result in no more than 30% off axis contribution. Accordingly,preferred planes for fixing one or more implants are those within 17.5degrees of perpendicularity.

FIG. 4 shows a top view of a cervical vertebral body 41. In this view,it is possible to identify the spinous process 42, the superiorarticular processes 43 and 44, and the lateral aspects 45 and 46 of thesuperior articular processes 43 and 44.

Methods described permit the surgeon to install hardware at two,preferably three locations, generally aligned with the disc space, andto pass one or more implants between the locations to treat a singlespinal level. Hardware may be installed on a first vertebral body, asecond vertebral body or both in order to assist in fixation of animplant between vertebral bodies. A first vertebral body may be asuperior vertebral body while a second vertebral body may be an inferiorvertebral body, or vice versa.

In a preferred embodiment, hardware is fixed on a superior vertebralbody at the spinous process and is the sole point of fixation on thesuperior vertebral body. Fixation on an inferior vertebral body may bebilateral, such as at two locations extending laterally outwardly onopposite sides of the spinous process. For example, in one embodiment,two implants may be fixed to the spinous process of a superior vertebralbody and may extend laterally outward such that one implant is fixed toa first pedicle of an inferior vertebral body and the other implant isfixed to a second pedicle of the inferior vertebral body. In anotherembodiment, two implants fixed to the spinous process of a superiorvertebral body may extend laterally outward such that one implant isfixed to a first mamillary process of an inferior vertebral body and theother implant is fixed to a second mamillary process of the inferiorvertebral body. In some embodiments, fixation could be unilateral usinga sufficiently stiff implant.

The location for fixation on the inferior vertebral body is dependent onthe level of the spine being operated on. In the lumbar spine, thepreferred location for fixation is in the region from the pediclesuperiorly and medially onto the mamillary process, bilaterally. At theL5-S 1 spinal level, the preferred location for fixation is to thesacrum, generally aligned with the disc space. In the cervical spine,the preferred location for fixation to the inferior vertebral body isthe lateral aspect of the superior articular process.

Various implants are provided which may provide torsional stabilizationto the spine. These implants may be configured to extend in tensionbetween a superior vertebral body and an inferior vertebral body in aplane generally aligned with the disc space to provide torsionalstabilization. The implants may be fixed to one or more locations of thesuperior vertebral body and the inferior vertebral body. As used herein,the term “fix” means direct fixation of an implant to a vertebral body(such as by tying the implant around the vertebral body) or indirectfixation of an implant to a vertebral body by using fixing a fixationdevice such as a staple, anchor, endobutton or outrigger.

As illustrated below, the implants may be of various shapes and sizes.While some of the implants may be comprised of relatively stiffmaterials including metals such as titanium and stainless steel andnon-metals such as carbon fiber, in a preferred embodiment, the implantis comprised of a material that allows for sufficient strength andflexibility. In some embodiments, the stabilizing implant is flexibleand can be fashioned of a variety of biocompatible materials includingpolymeric surgical fabrics using resorbable and/or non-resorbablepolymers in the form of weaves, braids, knits and embroidery. In someembodiments, the stabilizing implant comprises a solid polymer includingresorbable and non-resorbable polymers, autograft soft tissue, allograftsoft tissue, allograft or autograft bone, metal fabrics, metal meshes orsolid metal components in addition to titanium and metal, as well asbiocompatible composites. Having a flexible implant allows the implantto be used advantageously with a variety of hardware at specificlocations of the spine. Having a flexible implant also allows for easein fixing the implant using the preferred methods of the presentapplication, which may allow the implant to be grabbed, pulled andplaced in tension in between locations. A flexible implant also permitslaying the implant over the posterior part of the facet so as to take anon-linear path between points of fixation. A flexible implant alsoallows for passing the implant from one location to another, as will bedescribed later in this specification. As an implant may contact bonebetween its anchor points and will lie within muscle, it may also beadvantageous to have the implant coated with a biocompatible hydrophilicmaterial or with a biocompatible hydrogel so that friction may bereduced between the implant and the biological material that itcontacts. Besides flexibility, an implant's stiffness may be consideredwhen providing torsional stabilization using one or more implants. Thestiffness of an implant can be varied by using different types ofmaterials and/or by adjusting the geometry of the implant to provide avariety of stiffening effects.

Implants of various geometries are now provided. FIG. 5 shows oneembodiment of an implant 51 having a generally rounded cross-section.FIG. 6 shows one embodiment of an implant 61 having a generallyrectangular cross-section. FIG. 7A shows one embodiment of an implant 71having a tubular cross-section.

In a preferred embodiment, the implants are comprised of a flexible,compliant material that allows the implant to be shaped with ease in andaround spinal segments. FIG. 7B shows the effect of using the complianttube implant 71 of FIG. 7A when passing the implant around a piece ofbone 72. As shown, the cross section at both ends 73 and 74 aregenerally tubular while in the central portion 75 of the implant 71, thethickness of the implant is reduced. This reduction in thicknesscorresponds to a collapse of the tube in this region which may bebeneficial in applications where the implant comes in contact with thebone. Allowing the implant 71 to be flexible and work around the bone 72reduces wear and tear to the bone. In addition, in some embodiments,deformation of the implant 71 at its central portion 75 can result inincreased strength of the implant by deformation strengthening at thecentral region of the implant.

FIG. 8 shows a filled tubular implant 81 according to one embodiment. Inthis embodiment, the implant is again tubular in cross section 82, butthe tube is also filled with material 83. Filler material 83 can act asa cushion for various loads on the implant. Examples of filler materialin the tubular implant 81 include elastic materials such as rubber,viscoelastic materials and advanced polymers, metal monofilament, animalderived materials (allograft, autograft) and combinations of the above.The benefits of this structure are that the inner material 83 may beused as the load carrying element, while the tube 82 is designed tobetter integrate with the adjacent material. For example, the innermaterial could be a polymer or metal monofilament and the external tubecould be highly porous. The monofilament provides the strength totorsionally stabilize the spinal level, whereas the highly porousexternal tube permits integration of the implant with adjacent softtissue.

The stabilizing implant may be fixed to the bone using a variety ofavailable means, including screws, staples, anchors (including softtissue anchors) and other types of hardware. The hardware can befashioned of a variety of biocompatible materials, including resorbableand non-resorbable polymers, metals, as well as assemblies of polymersand metals. Besides or in addition to using hardware, an implant may befixed to bone using a surgical adhesive.

FIG. 9A shows a staple 91 which can be used as an anchor in the presentapplication. FIG. 9B shows an anchor 91 assembled to an implant 92. Theimplant 92 corresponds to the implant 61 of FIG. 6 having a generallyrectangular cross-sectional area. Methods and means of assembling animplant to an anchor are described later.

FIG. 10 shows an embodiment of an anchor 101 comprised of a threadedbone anchoring portion 102 and an implant receiving portion 103. Thehole 104 in the implant receiving portion 103 can be configured tomatch, but be a slightly oversized version of the cross section of theimplant.

FIG. 11 shows an exploded view of an embodiment of an anchor comprisedof a bone anchoring component 112 and an implant attachment post 113.The bone anchoring component is threaded externally to attach to thebone, and the thread could be self-tapping to minimize the number ofinstruments required to insert the device. The bone anchoring component112 also features an internal threaded hole 114 to receive the threadedportion 115 of the implant attachment post 113. The implant attachmentpost 113 also has a cap 116 which can have a feature (not shown) topermit tightening of the implant attachment post 113 to the boneanchoring component 112.

FIG. 12A shows a front view of an offset anchor 121. The anchor has twoholes 122, 123. The first hole 122 is intended to receive a screw (notshown) that can be used to fix the anchor to the bone. The second hole123 is intended to receive an implant.

FIG. 12B shows a side view of the offset anchor 121 shown in FIG. 12A.As seen in the side view, the anchor permits attachment at one location(using hole 122) while fixing the implant at a second location by usinghole 123. Fixation of the implant at hole 123 could be accomplished by avariety of means and methods, which will be described later. Using anoffset anchor, such as shown in FIGS. 12A and 12B, advantageously allowsfor fixation of the implant at a suitable bone site, such as thepedicle, while still permitting the implant to be generally aligned withthe disc space. Using an offset anchor advantageously permits fixationof implants to locations further away from the disc space, such as tosites which may have greater volumes of bone or locations that areeasier to access.

FIG. 13 shows a posterior (rear) view of a lumbar vertebral spine. Asshown, a single spinal level is composed of the disc targeted fortreatment 131, a superior vertebral body 132, and an inferior vertebralbody 133. In this view, it is possible to visualize the spinous process134 of the superior vertebral body 132, as well as the mamillaryprocesses 135 and 136 of the inferior vertebral body 133.

FIG. 14A shows a posterior (rear) view of a lumbar vertebral spine withan implant and anchors applied. The implant 141 is affixed at themamillary process of the left side 135 of the inferior vertebral body133 by a staple 142. It passes below the spinous process 134 of thesuperior vertebral body 132, wraps up along the right side of thespinous process, through a hole drilled in the spinous process, backdown along the left side of the spinous process and then loops 144 underthe spinous process. It then continues to the mamillary process of theright side 136 of the inferior vertebral body 133 where it is affixed tothe bone using a staple 143.

FIG. 14B shows a sagittal (side) view of the implantation system shownin FIG. 14A. As in FIG. 14A, the implant 141 is affixed at the mamillaryprocess of the left side of the inferior vertebral body 133 by a staple142. The implant 141 wraps under the spinous process 134 of the superiorvertebral body 132, loops through a hole 145 in the spinous process, andthen passes below 144 the spinous process and continues to the rightside (not shown).

As an alternative to passing the implant through a hole in the spinousprocess and as a way to reduce bone trauma, the implant could loop overthe entire spinous process instead of passing through a hole in thespinous process. While this approach would require less bone trauma, itmay result in a less stable implant (as it is not as rigidly anchored tothe spinous process of the superior vertebral body and may be subject toloosening by sliding anteriorly along the spinous process), and mayrequire more soft tissue stripping of the muscles that attach to thespinous process.

Fixation to locations on the inferior vertebral body, such as at themamillary processes or the pedicles, can be accomplished by using avariety of hardware, including the staple shown in FIG. 9A and the boneanchors shown in FIGS. 10 and 11. Additionally, there are a variety ofmetal and polymeric screws, some made of either resorbable and/ornon-resorbable polymers, that can be used to anchor an implant to theinferior vertebral body. In some embodiments, the anchor comprises asuture anchor capable of being fixed into the inferior vertebral body.Additionally, other mechanical means of fixation include screws andnails to fix the implant to the inferior vertebral body. In these cases,the mechanical means would pass through the implant and into theselected boney location.

Alternatively, a surgical adhesive could be used to fix the implantdirectly to the bone and eliminate some or all hardware. In this case,the implant would be put in proximity to the desired bone location, theadhesive applied to either the implant or the bone location and theimplant held against the bone until the adhesive set, using whatevertechnique the adhesive producer suggests for setting the adhesive.

Various hardware, besides those used as fixation devices to an inferiorvertebral body, may also be used with the spinous process of thesuperior vertebral body. Hardware, including alternate anchors, may beused to fix the implant to the spinous process. When using hardware tofix the implant to the spinous process, it may be easier to have two ormore separate implants. In one embodiment, a first implant can extendfrom the left side fixation on the inferior vertebral body to thespinous process of the superior vertebral body, while a second implantcan extend between the right side fixation on the inferior vertebralbody and the spinous process of the superior vertebral body. Theimplants used in such a configuration can include any of those implantsdescribed in FIGS. 5, 6, 7A and 8 and any combination thereof. Theseimplants can be chosen or made to have an appropriate length to span thedistance on one side from an inferior vertebrae to a superior vertebrae.Other suitable implants, may include for example, one or more sutures orwires.

Various hardware are now described which may be used to fix one or moreimplants to the superior vertebrae, and more specifically, the spinousprocess of the superior vertebrae. In some embodiments, the hardwareused for fixation to the spinous process may also be used to fix one ormore implants to the inferior vertebral body. The hardware can beattached to the spinous process of the superior vertebrae by engagingthe spinous process and/or by engaging a hole through the spinousprocess. Using hardware described below (which includes but is notlimited to turnbuckles and outriggers) advantageously provides a stablemechanism for securing the implants at or near the spinous process. Inaddition, using hardware of different geometries provides the additionalbenefit of allowing for attachment of one or more implants either at thespinous process or near the spinous process (e.g., below or along theside of the spinous process), thus providing the flexibility for fixingan implant at various locations to optimize torsional stability fromsubject to subject. The use of hardware also permits distributing forceapplied to the spinous process over a sufficiently large area so as toavoid local failure of the cancellous bone that constitutes the spinousprocess. Also, hardware can be manufactured out of a resorbable materialso that the device has a temporary function—providing torsionalstability until the resorbable material decays to the point where themechanical function of the device is lost.

FIGS. 15A, 15B and 15C show a front exploded, right side and anassembled bottom section view respectively of a turnbuckle 151. It iscomposed of a body 152, two nuts 153 and 154, and two outriggers 155 and156. The nuts permit clamping of the body to the spinous process. Theoutriggers permit fixation of the implant to the turnbuckle.

The body 152 has an external thread on the outside that mates with theinternal thread on the nuts 153 and 154. The body also has two internalthreads 157 and 158 (shown in FIG. 15C) that receive the outriggers 155and 156. The internal thread 157 is cut in the opposite direction as theinternal thread 158 (making one a “right handed” thread and the other a“left handed” thread). Two flats 159 and 160 are cut on the outside ofthe body 152.

The outriggers 155 and 156 each have external threaded shafts 161 and162 respectively. Consistent with the body, the threaded shaft 161 iscut in the opposite direction as the external thread on the shaft 162.The threaded shaft 161 is cut in the same direction as the internalthread 157 of the body; the threaded shaft 162 is likewise cut in thesame direction as the internal thread 158 of the body. The end of theoutriggers 163 is configured to receive an end of the implant and topermit fixation of the implant to the end of the outrigger.

FIG. 16 shows a posterior (rear) view of a lumbar vertebral spine withtwo implants 165 and 166, two anchors 167 and 168 applied to fix theimplants to the inferior vertebral body, and a turnbuckle 151 havingoutriggers 155 and 156 to attach the implants to the spinous process.Fixation of the implants 165 and 166 to the outriggers 155 and 156 couldbe by a variety of means described below. No fixation of the implants tothe outrigger is shown. Once the implants are fixed bilaterally via theanchors to the inferior vertebral body and the implants fixed to theoutriggers (but prior to tightening down on the nuts 153 and 154 toclamp the turnbuckle to the spinous process), the two implants can besimultaneously tightened. This is accomplished by aligning a wrench withthe flats 159 and 160 (shown in FIGS. 15A and 15B) on the body androtating. Rotation in one direction will result in simultaneoustightening; rotation in the opposite direction will result in loosening.After reaching the appropriate tightness, the turnbuckle can then beclamped to the spinous process by tightening both nuts 153 and 154.

While there are some circumstances where due to anatomy and surgeonpreference, it is possible to fix through the spinous process, there areother times when it is preferable to fix the implants to a locationbelow the spinous process. One possible time is when fixation to theinferior vertebral body is at the level of the pedicle, as shown in FIG.1 and it is desired that the implants are generally aligned with thealternative plane 18 of FIG. 1. Using various hardware as described inthis application to engage the spinous process can help to facilitateplacement of an implant to a desired location below the spinous process.

FIGS. 17A and 17B show exploded views of an alternative embodiment of anoutrigger 171 for fixing two implants to a location below the spinousprocess of the superior vertebral body. The outrigger 171 has a stemportion 172 that mechanically couples the outrigger to a nut 173. Asshown, the stem portion 172 of outrigger 171 fits within the nut 173.The stem portion 172 and nut 173 can be held together via a screw 174that passes through the stem portion 172 and threads into the nut 173.The outrigger also has two holes 175 and 176 respectively that canreceive one or more implants. It should be noted that it is preferableto have the holes 175 and 176 angled with respect to the outrigger 171so as to put the holes in alignment with the overall direction of theimplant from its fixation point on the inferior vertebral body or inalignment with an intermediate location between fixation point and theoutrigger where the implant, when tensioned, can follow a linear path tothe outrigger 171.

FIG. 17C shows an additional side view of the outrigger 171 of FIG. 17A.As best seen in FIG. 17C, the stem portion 172 of outrigger 171 is oval.The advantage of this shape is that it couples the outrigger 171 withthe nut 173 when attempting to twist about the long axis of the stemportion 172. In turn, it is preferable that the outrigger stem 172 ofthe outrigger 171 be put through a hole in the spinous process thatmatches the shape of the stem portion 172, thus transferring any twistinduced by the implants directly to the bone of the spinous process andlimiting any rotations due to twist.

When using hardware to fix an implant to a vertebral body, it may bepreferable to clamp the implant to the hardware instead of using one ormore knots to fix the implant to the hardware. FIG. 18A shows a clamp181 that can be used to fix the implant. The clamp 181 is shown in usewith an implant 185 in FIG. 18B.

FIG. 19 shows a crimping instrument suitable for fixing the clamp to theimplant. The instrument has two handles 191 and 192, two jaws 193 and194 and portions of a cavity 195 and 196 created in the jaws. A band1992 is pinned 1993 and 1994 onto the jaws 193 and 194 to hold the pin1991 in place. Hinge pins 197, 198, 199 and 1991 and their relativepositions permit a multiplication of the force generated at the handlesto be applied to a clamp placed in the portions of the cavity 195 and196.

The use of the clamp 181 is shown in FIG. 18B. The implant 182 is passedthrough a hole 183 in the hardware 184 and then passed through the clamp181. Once assembled, one end of the implant 185 would be held taughtusing a hemostat or similar device. A crimping instrument, similar tothat shown in FIG. 19, would then be used to hold the clamp 181 tight tothe hardware 184. The crimping instrument would then be actuated toplastically deform the clamp 181 around the implant 182, thus preventingthe implant from pulling through the clamp and fixing the implant to theoutrigger.

FIG. 20A shows an alternative clamp 201 that can be used to fix theimplant. The cavity 206 is sized to fit two implants. As shown in FIG.20B, an implant 202 is passed through the clamp 201, through a hole 203in the hardware 204, wrapped around the hardware 204 and back throughthe clamp 201 such that the free end of the implant 205 is turned backonto the previously fixed end of the implant 202. Once assembled, oneend of the implant 205 would be held taught using a hemostat or similardevice. A crimping instrument, similar to that shown in FIG. 19, maythen be used to crimp the clamp 201 to both parts of the implant 202 and205. The advantage of this approach is that the clamp 201 does not needto contact the hardware 204, eliminating one possible wear couple. Thedisadvantage to this approach is that the clamping is done deep to thehardware, if the hardware is an outrigger or such as described in FIG.17A.

To ease fixation of an implant to hardware, it may be preferable to havea split clamp 271 as shown in FIG. 27. In this configuration, the clamp271 features a split 272 along its length. The split 272 permitsinsertion of an implant from the side of the clamp 271. Followinginsertion, the clamp is crimped by a tool such as that describedpreviously.

Generally, fixation of an implant to hardware can be accomplished by avariety of means, which are dependent on the type of hardware employed.For hardware such as nails, screws and staples including those describedin FIGS. 9A and 11, the hardware could pass through the implant and theninto the bone where the implant is to be fixed. For hardware that has amember around which the implant can pass, such as those described inFIGS. 9A, 10, 12A-12B, 15A-15C, 17A-C, 23A-B, 24A-B, 25A-25B and 26A-B,the implant could be tied to the member, hitched to the member, knottedafter passing through a hole in the member or crimped to the member.Additionally, an implant can be fixed to hardware having a member aroundwhich the implant can pass by passing the implant around the member,doubling the implant on itself (as shown in FIG. 20B), and then using avariety of mechanical means to fix the implant to itself. These includesutures, staples and rivets, as well as clamps such as those shown inFIG. 18A, FIG. 20A and FIG. 27. If the implant were suitably porous, forexample a fabric, or chemically appropriate to develop a chemical bondbetween the implant and the adhesive, an alternative means of fixationis the use of a surgical adhesive, such as cyanoacrylate or fibrin glueto fix the implant to the hardware. The implant would be wrapped aroundor through the hardware and the adhesive used to hold the implant toitself.

A surgical adhesive could also be used to fix the implant directly tothe bone and eliminate some or all hardware. In this case, the implantwould be put in proximity to the desired bone location, the adhesiveapplied to either the implant or the bone location and the implant heldagainst the bone until the adhesive set, using whatever technique theadhesive producer suggests for setting the adhesive.

FIG. 21 shows a posterior (rear) view of a lumbar vertebral spine aspreviously described in FIG. 13, having two implants 211, 213 attachedto locations of an inferior vertebrae 133 using two anchors 212, 214.The implants are also attached to the spinous process 134 via anoutrigger 171. As shown, a single spinal level is composed of the disctargeted for treatment 131, the superior vertebral body 132, and theinferior vertebral body 133. In this view, it is possible to visualizethe spinous process 134 of the superior vertebral body 132, as well asthe mamillary processes 135 and 136 of the inferior vertebral body 133.

An implant 211 is affixed at the mamillary process of the left side 135of the inferior vertebral body 133 by an anchor 212. The implant 211passes towards the midline, where it is affixed to an outrigger 171.Fixation of the implant 211 to the outrigger 171 could be by a varietyof means previously described. No fixation of the implant to theoutrigger is shown. A second implant 213 is affixed at the mamillaryprocess of the right side 136 by an anchor 214. It is attached to thespinous process 134 of the superior vertebral body 132 via the outrigger171. Fixation of the implant 213 to the outrigger 171 could be by avariety of means previously described. No fixation of the implant to theoutrigger is shown. The outrigger 171 is clamped together to the spinousprocess via a nut 173 and screw 174.

FIG. 22 shows an alternative assembly using the outrigger 171 of FIG. 21with a single implant 221. In this assembly, the hardware used is thesame (anchors 212 and 214, outrigger 171 and nut 173 clamped together tothe spinous process via a screw 174). A single implant 221 is used thatis fixed to the anchors 212 and 214 on the inferior vertebral body andwhich passes through both holes in the outrigger 171. Fine tensioning ofthis assembly could be accomplished by sliding shims between the implantand the outriggers, with different thickness shims resulting indifferent amounts of tensioning.

A variety of alternative outriggers are also possible. FIG. 23A and FIG.23B show views of one such outrigger 231. The outrigger 231 has two arms232 and 233 connected by a reduced section hinge 234 that permitsdeformation of the outrigger. The hole 236 as shown in FIG. 23Brepresents a hole through which an implant could pass and thus besecured to the outrigger. A hole for this purpose would be in each arm232 and 233. The orientation of the hole 236 could be in a variety ofdirections so as to put the hole in alignment with the overall directionof the implant from its fixation point on the inferior vertebral body orin alignment with an intermediate location between fixation point andthe outrigger where the implant, when tensioned, can follow a linearpath to the outrigger. Additionally, there is a secondary fixation hole235 that could receive a screw (not shown) in both arms 232 and 233.

The outrigger of FIG. 23A could be assembled to the spinous processusing the following procedure. A hole of appropriate shape is cut orpunched through the spinous process. One arm of the outrigger (either232 or 233) is passed through the hole so that the arms are separated bythe spinous process, and the reduced section hinge lies generally withinthe hole created in the spinous process. A screw could then be drilledthrough the hole 235 in outrigger arm 233, through the spinous processand then through a preexisting hole in outrigger arm 232.

A second method for assembling the outrigger of FIG. 23A to a spinousprocess is as follows. A small hole is created in the interspinousligament at the superior surface of the spinous process. One arm of theoutrigger (either 232 or 233) is passed through the hole so that thearms are separated by the spinous process, and the reduced section hingelies generally between the targeted spinous process and the adjacentspinous process. A screw could then be drilled through the hole 235 inoutrigger arm 233, through the spinous process and then through thepreexisting hole in outrigger arm 232. This method could be advantageousfor small spinous processes, such as those seen in the cervical spine.In the cervical spine, it may not be desirable that the outrigger arms232 and 233 extend below the spinous process.

Fixation of one or more implants could be done using the means andmethods already described for attaching implants to hardware.

As an alternative to having to pass one or more implants through holesin an outrigger as described above, it is also possible to have a postoutrigger 241, as shown in FIG. 24A and FIG. 24B. In one possibleconfiguration, the arms are not symmetric, with arm 242 extending longerthan arm 243. The arms 242 and 243 are connected through a reducedsection hinge 244. Fixation of one or more implants to the outrigger 241is intended to occur along the reduced section length 245. The increasedsection 246 lies below the reduced section as a stop or limit to preventthe one or more implants from sliding off of the outrigger 241. Botharms 242 and 243 have an aligned hole 247 that could receive a screw(not shown) to fix the outrigger 241 to the spinous process.

The outrigger of FIGS. 24A and 24B could be assembled to the spinousprocess using the following procedure. A hole of appropriate shape iscut or punched through the spinous process. The short arm of theoutrigger 243 is passed through the hole so that the arms are separatedby the spinous process, and the reduced section hinge lies generallywithin the hole created in the spinous process. A screw could then bedrilled through the hole 247 in outrigger arm 243, through the spinousprocess and then through the preexisting hole in outrigger arm 242.

Fixation of one or more implants to the outrigger 241 could be doneusing the means and methods already described for attaching implants tohardware.

An alternative spinous process anchor is also embodied that permits asimilar means of fixation of the implant but without the outrigger.FIGS. 25A and 25B show front and side views respectively of such ananchor. It is composed of top 251 and bottom roofs 252 which areconnected by spaced apart uprights 253 and 254. The top and bottom roofs251 and 252 preferably have a multitude of holes 255 or features topermit bone and soft tissue ingrowth into the anchor. The overall shapeof the roofs 251 and 252 are intended to snugly fit within a holecreated in the spinous process.

The anchor of FIGS. 25A and 25B could be assembled to the spinousprocess using the following procedure. A hole of appropriate shape iscut or punched through the spinous process. The anchor would then bepressed into the created hole. Implants would then be fixed to theanchor by means of the spaced apart uprights 253 and 254. Preferably,the distance from the outside surface of uprights 253 and 254 is on theorder of the thickness of the spinous process so that the implants arelocated in close proximity to the bone of the spinous process. Thispermits tissue ingrowth into the implants and the anchor thus providingthe system with biological fixation.

Modifications to the anchor of FIGS. 25A and 25B are also contemplatedwhich could enhance the short term fixation of the anchor. One set offeatures that could enhance short term fixation include rings 261 orpartial rings 262 attached to the top 251 and bottom roofs 252 at oneend as shown in FIGS. 26A and 26B. The ring 261 and partial ring 262could accommodate screws to provide temporary fixation to the spinousprocess. Alternatively, teeth could be cut on the outside of the top andbottom roofs to increase resistance to relative motion of the anchorwith respect to the spinous process. In a similar manner, the outside ofthe top and bottom roofs could be made of porous materials such asZimmer's trabecular metal or a metal porous coated with beads or plasmaspray.

Fixation of the one or more implants to the anchor of FIGS. 25A and 25B,as well as to the anchor of FIGS. 26A and 26B could be done using themeans and methods already described for attaching implants to hardware.The uprights would serve as the members about which the implants couldbe passed.

Fixation to the spinous process could also be accomplished with athimble 281 shown in FIGS. 28A and 28B. It has two arms 282 and 283 withan opening at one end 284. It has a curvilinear groove 285 in crosssection that runs along both arms 282 and 283 and serves to align theimplant with the thimble.

The thimble 281 could be assembled to a spinous process in the followingmanner. A small hole is created in the interspinous ligament at eitherthe superior or inferior surface of the spinous process. One arm of thethimble (282 or 283) is passed through the hole so that the arms areseparated by the spinous process. This method could be advantageous forsmall spinous processes, such as those seen in the cervical spine. Tomate with a spinous process in the cervical spine, it may beadvantageous to have the inner aspect of the thimble shaped to match thebone receiving it. Also, it may be advantageous to fix the thimble tothe spinous process and this could be accomplished with a screw driventhrough a hole (not shown) in one or both of the arms 282 or 283 of thethimble 281.

Once the thimble is in place, an implant can pass to the spinousprocess, wrap around the spinous process while in alignment with thethimble, be tightened so as to bring the implant into contact with thethimble, then passed to the inferior vertebral body for furthertensioning and fixation.

In summary, a variety of hardware has been described that can be used tofix one or two implants in a position generally aligned with the discspace between adjacent vertebral bodies so as to treat a targeted discand limit or prevent torsion of the targeted spinal disc.

To perform the insertion of the hardware and implants contemplated in aless invasive way, various instruments may be used by the surgeon. FIG.29 shows the top view of a multi-functional surgical instrument 300. Theinstrument 300 has a handle 292, and three arms 293, 294, 295. Arms 293and 295 are symmetric about a line through the handle 292 and each armfeatures two holes 296 and 297. The central arm 294 has a stationaryelement 299 and a movable arm 298. The movable arm rotates about a pin2991. At the handle end of the movable arm, there is a ratchet mechanism2981 to permit controlled positioning of the movable arm 298 withrespect to the stationary arm 299. The ratchet mechanism 2981 mates witha ratcheting element (not shown) on the handle 292. Motion of themovable arm is permitted in one direction of rotation about the pin 2991and prevented in the opposite direction by means of teeth (not shown).To hold the movable arm in position, there is a spring element 2982 inthe space between the movable arm 298 and the handle 292. In someembodiments, the arms have a curvature that follows the contour of asubject's skin. While in some embodiments the arms may contact asubject's skin, in other embodiments, the arms are lifted and removedfrom the subject's skin.

The central arm 294, the stationary element 299, movable arm 298, thepin 2991, the ratchet mechanism 2981 and the spring element 2982 form abone clamp. The purpose of the bone clamp is to hold the surgicalinstrument to the spinous process. The faces of the bone clamp 2992 and2983 may be configured to mate with particular bone geometry. Also, thebone clamp elements may be modified to serve as a combination bone punchand bone clamp so that it could create a hole in the spinous processbased on the geometry of the faces of the bone clamp 2992 and 2983 andthen hold that position. Specifically, the faces of the bone clamp 2992and 2983 could be pointed so that when the movable arm 298 is movedtowards the handle 292, bone is crushed to create a hole in the spinousprocess.

The holes 296 and 297 of the arms 293 and 295 are oriented to align aseries of locations. FIG. 30 shows an alternate top view of theinstrument 300 of FIG. 29 attached to a lumbar spine. The holes 297 arealigned with the location desired for fixation to the inferior vertebralbody. As shown in FIG. 30, one possible location 301 is at theintersection of the mamillary process 302 with the pedicle 303.

Depending on the subject, the size of the instrument may vary. Inaddition, specific features of the instrument, such as the clampingportion, may vary. In some embodiments, different instruments are usedto accommodate different subjects, while in other embodiments, a singleinstrument is provided that is adjustable. The instrument may havedetachable portions (e.g., the arms) that are removable and can bereplaced subject to subject. Alternatively, the position of the holescould be made adjustable by creating hollow tubes, which represent theholes 296 and/or 297, and configuring the instrument to permit the tubesto controllably slide with respect to the arms.

The holes 296 are aligned with the point 306 on or near the spinousprocess 305 of the superior vertebral body and a second point 304 justposterior to bone that prevents one or more implants from traversing alinear path between the points of fixation on the inferior vertebralbody to the fixation on the superior vertebral body. In the exampleshown in FIG. 30, the second point 304 is just posterior to the tip ofthe mamillary process of the inferior vertebral body. It is also notedthat the axis of the hole 296 on the right arm 295 may intersect withthe axis of the hole 297 on the left arm 293 of the instrument.Likewise, the axis of the hole 296 on the left arm 293 may intersectwith the axis of the hole 297 on the right arm 295 of the instrument.

FIG. 31A shows a front section view as defined by section line A-A inFIG. 29 of the multi-functional surgical instrument of FIG. 29, with themovable arm removed for the purposes of clarity. The holes 296 and 297in the arms 293 and 295 could be circular or non-circular in shape. Alsoas shown, the holes 296 and 297 are aligned in the same plane, which iscoincident with the position of the bone clamp (not shown). A cavity 311is made in the lower part of the instrument to receive the movable arm.

FIG. 31B shows an alternative front section view as defined by SectionLine A-A in FIG. 29 of a surgical instrument, with the movable armremoved for purposes of clarity. In this embodiment, the holes 296 and297 are aligned but offset from the bone clamp. This embodiment could beuseful when it is desired to use an outrigger to fix to a position belowthe spinous process, or when the implant is intended to pass under thespinous process or around the spinous process.

FIG. 31C shows yet another alternative front section view as defined bySection Line A-A in FIG. 29 of a surgical instrument, with the movablearm removed for purposes of clarity. In this embodiment, the holes 296and 297 are offset in opposite directions.

A variety of hardware are intended to pass through each hole 296 and297, and it is preferable that each hole 296 and 297 be of the samecross section so as to be capable of receiving the same set of tools.Further, it is preferable that the shape of the holes be matched to theshape of the implants being used and also to the shape of the fixationto be used on the inferior vertebral body. For example, an implant ofthe shape shown in FIG. 6 would be preferably matched to a staple typefixation of FIG. 9A which in turn would be preferably matched with agenerally oval shape cross section of holes 296 and 297.

FIG. 32A illustrates an oblique view of an alternate embodiment of amulti-functional instrument 708. The instrument 708 includes a handle711, tines 715, anchor holes 732 and passing holes 740. FIG. 32Billustrates an alternative top view of the multi-functional instrument,and points out additional features of the instrument, including a fixedarm 294, a movable arm 2, a pin 2991 and a fixed arm drill guide 4.

FIGS. 32C and 32D show a top view and side view, respectively, of analternate embodiment of a multi-functional surgical instrument 1201having a combination anchor and passing hole 1205 according to oneembodiment. A multi-functional instrument as shown in FIGS. 32C and 32Dmay be used in conjunction with various types of hardware and implants(including suture anchors) to provide torsional stabilization. Theinstrument 1201 includes two handles 1202, two tines 1203, a hinge 1204and a combination anchor and passing hole 1205. The axis of thecombination anchor and passing hole 1205 is shown as 1206. While themulti-functional instruments shown in FIGS. 29-32D may not be necessaryto accomplish the methods of torsional stabilization described herein(for example, several different instruments may be used for clamping andalignment), using the multi-functional instruments described hereinallow for advantageously using a single instrument capable of performingmultiple functions with precision and accuracy.

In addition to the instruments and hardware described above, others mayalso be used to facilitate the methods, systems and apparatusesdescribed herein. FIG. 33 shows a dilator 321. It has a leading end 322which transitions the dilator from the cross section 323 of the trailingend to a point. The leading end 322 can be configured as a bullet nose,a conical end or any other gradually tapering surface suitable for bluntdissection of the muscle tissue of the neck and back. The cross section323 is selected so that the dilator has a slidable fit with the holes296 and 297 of the instrument.

FIG. 34 shows a cannula 331. It has a leading end 332 which transitionsthe dilator from the cross section 333 of the trailing end to an edge.The leading end 332 can be configured as a portion of a sphere, aportion of a cone or any other gradually tapering surface suitable forblunt dissection of the muscle tissue of the neck and back. The crosssection 333 is configured so that the dilator has a slidable fit withthe holes 296 and 297 of the instrument. The inner hole 334 of thecannula is configured to be a reduced size version of the cross section333.

A reduced size dilator is also contemplated, similar to that shown inFIG. 33. The reduced size dilator would have a smaller cross section 323to create a slidable fit with the inner hole 334 of the cannula. Theassembly of the cannula and the reduced size dilator could be used todissect tissue in a path followed by removal of the reduced size dilatorto create a working channel within the cannula.

FIGS. 35A and 35B show a tamp 341. It has a leading end 342 which has areduced size surface 344 suitable for impacting or pushing on theimplant or anchor as necessary. It has a cross section 343 that matchesthe holes 296 and 297 of the instrument and permits the tamp to slidewithin the hole. It can also be made in a reduced section size so thatthe outside of the tamp fits slidably within the hole 334 of thecannula.

FIG. 36 shows a hooker 351. It has a leading end 352 and a trailing end353. The leading end 352 can be configured as a portion of a sphere, aportion of a cone or any other gradually tapering surface suitable forblunt dissection of the muscle tissue of the neck and back. The trailingend 353 can be shaped to be a portion of the hole 296 and 297 so that itcan fit slidably within a hole, while not filling the entire space ofthe hole 296 and 297. The hooker 351 has a reduced section portion 354.Adjacent to the reduced section are curved surfaces 355 and 356.

FIG. 37 shows a portion of a grabber 361. It has two pieces, a slider362 and a fixed element 363. It has a leading end 364 and a trailing end365. The leading end 364 can be configured as a portion of a sphere, aportion of a cone or any other gradually tapering surface suitable forblunt dissection of the muscle tissue of the neck and back. The trailingend 365 is composed of portions of both the slider 362 and the fixedelement 363. The trailing end 365 can be shaped to fill a portion of thehole 296 and 297 so that it can fit slidably within the hole, while notfilling the entire space of the hole 296 and 297. The fixed element 363is of reduced section until the leading end 364. Between the slider 362and the leading end 364 is a space 366. To best grab an implant, theslider end 367 adjacent to the space 366 can be configured to mate withthe trailing portion 368 of the leading end 364. The mating elements 367and 368 provide a means to grab an implant between them.

Incorporation of the grabber 361 into an instrument is contemplated asshown in FIG. 39, which is a Kerrison type rongeur configured as agrabber. The Kerrison is a widely used surgical instrument composed of afixed element 381, a slider 382, a moveable handle 383 and a hinge 384.The movable handle 383 has a portion of it extending to and fixing tothe slider 382. When the movable handle 383 is rotated about the hinge384 towards the handle 385 of the fixed element 381, the slider 282 ismoved towards the leading end 386.

In some configurations, it may be desirable to hold an implant whileletting the implant slide relative to the holding instrument. FIG. 38shows a portion of a puller 371 intended to hold an implant whileletting the implant slide relative to the holding instrument. It has twopieces, a slider 372 and a fixed element 373. It has a leading end 374and a trailing end 375. The leading end 374 can be configured as aportion of a sphere, a portion of a cone or any other gradually taperingsurface suitable for blunt dissection of the muscle tissue of the neckand back. The trailing end 375 is composed of portions of both theslider 372 and the fixed element 373. The trailing end 375 can be shapedto fill a portion of the hole 296 and 297 so that it can fit slidablywithin the hole, while not filling the entire space of the hole 296 and297. The fixed element 373 is of reduced section until the leading end374. Between the slider 372 and the leading end 374 is a space 376. Tobest pull an implant, the slider end 377 adjacent to the space 376 canbe configured as a portion of a cylinder while the trailing portion 378of the leading end 374 has a similar cylindrical shape. When the slider372 is slid towards the leading end 374, it is possible to hold animplant in the space 376. Due to the small contact area resulting fromthe cylindrical surfaces apposing each other, the implant will have anincreased tendency to slide. Incorporation of the puller into a Kerrisontype rongeur is analogous to that described for the grabber.

FIGS. 40A, 40B and 40C show a side view, top view, and front view,respectively, of an inserter 391. It has a leading end 392 with a matingsurface 393 that mates with an anchor intended to be impacted into placesuch as a staple. It has a trailing end 394 that slidably fits within acannula, such as that of FIG. 34. A reduced section portion 395 isadjacent to the leading end 392, which connects the leading end 392 withthe trailing end 394. The reduced section portion 395 helps to removematerial from the inserter such that there is space for an implant wheninserting an anchor preassembled with an implant, such as that describedin FIG. 9B. Additionally, the reduced section portion 395 permitspassing of grabbers, hookers and pullers below the inserter to snare theimplant. The mating surface 393 is reduced in size from the crosssection of the inserter 394, as shown in FIG. 40C, so as to permit animplant preassembled onto the anchor to pass adjacent to the matingsurface and into the reduced section portion 395.

FIGS. 41A, 41B and 41C show a side view, top view and front view,respectively, of an alternative inserter 401. The inserter has a leadingend 402 with a slot 403 that mates with an anchor intended to be rotatedinto place such as that shown in FIG. 10. It has a trailing end 404 thatslidably fits within a cannula, such as that of FIG. 34, but is of thelargest round cross section that can fit within the cannula. Adjacent tothe leading end 402 it has a reduced section portion 405 that connectsthe leading end 402 with the trailing end 404. The reason for thereduced section portion 405 is to remove material from the inserter sothat there is space for implant when inserting an anchor preassembledwith an implant. Additionally, the reduced section portion 405 permitsthe passing of grabbers, hookers and pullers below the inserter to snarethe implant. The leading end surface 406 is reduced in size from thecircular cross section of the inserter 404, as shown in FIG. 41C, so asto permit an implant pre-assembled onto the anchor to pass adjacent tothe leading end surface and into the reduced section portion 405.

It is conceived that a variety of alternative mating geometry could beincorporated into the alternative inserter replacing the slot 403 tomatch the anchor geometry.

FIG. 42 shows a front view of an alternative hooker 411. It has aleading end 412 and a trailing end 413. The leading end 412 is offsetfrom the trailing end and may be pointed to enhance its ability tocapture the implant.

FIGS. 43A, 43B and 43C show a combination tamp/inserter cannula 421. Thecombination tamp/inserter cannula has a leading end 422, a trailing end423 and a central bore 424. The leading end 422 is generally blunted forpushing on the implant. As seen in FIG. 43C, the central bore 424 iscircular in cross section, making it suitable to receive a screw andscrewdriver. The outside 425 is generally the shape of the cross sectionof the hole 297, except for a flat 426. The overall shape ensures thatthe combination tamp/inserter cannula 421 slidably fits with the hole297, while the flat 426 ensures that there is space within the hole forthe alternative hooker 411 previously described. This configurationensures that both the combination tamp/inserter cannula and thealternative hooker can be placed within the hole 297 of the instrumentof FIG. 29.

In sum, a variety of implant alternatives and hardware alternatives tofix the implant to the inferior and superior vertebral bodies have beendescribed. Additionally, a set of instruments have been described thatcan be used to assist the surgeon in positioning one or more implantsbetween the inferior vertebral body and the superior vertebral body suchthat the implant is aligned with the disc space.

A preferred surgical technique can now be described. The describedsurgical technique utilizes the surgical instrument 300 shown in FIG.29, although various surgical instruments may be used to perform thesurgical technique. The surgical technique can begin by having a surgeonidentify a spinal level to be treated. This step is optional, for insome embodiments, a spinal level location may have been pre-determined,such that identification of the spinal level need not be considered partof the surgical technique. A midline incision is made, progressing downto the level of the spinous process of the superior vertebral body. Thisstep is also optional, for in some embodiments, an incision may havealready been made as part of an open surgery. The surgical instrument ofFIG. 29 is clamped onto the sides of the spinous process of the superiorvertebral body. Using the holes 297 of the surgical instrument asguides, incisions are made that are aligned with the holes 297 of theinstrument. These incisions are made bilaterally, although in someembodiments, an incision need only be made unilaterally on one side.Optionally, a reduced size dilator and cannula can be assembled andintroduced through the holes 297 in the instrument and used to bluntlydissect down to the point of fixation on the inferior vertebral body. Inone embodiment, the dilator can be temporarily removed from the cannulato incise the fascial layer. The fascia may then be incised and thedilator reassembled to the cannula. The assembly is advanced to thepoints of fixation on the inferior vertebral body. The dilator iswithdrawn, leaving the cannula.

The anchor for fixation to the inferior vertebral body can be assembledto an implant, or preferably come preassembled to an implant. The anchoris put on an inserter. The inserter is passed through the cannula andused to fix the anchor to the fixation point. This is done bilaterally,although in some embodiments, the inserter may pass through the cannulaon one side unilaterally.

A grabber, hooker or puller can be introduced through the hole 296 onthe opposite arm of the surgical instrument 300 of FIG. 29 and advancedlaterally toward the implant. In one embodiment, an additional skinincision is made for the grabber, hooker or puller. When the grabber,hooker or puller contacts the cannula, the cannula is retracted until itclears the grabber, hooker or puller. The grabber, hooker or puller isthen further advanced to capture the implant. Once the implant iscaptured, the grabber, hooker or puller is retracted to bring theimplant to the spinous process of the superior vertebral body. This stepis repeated on both sides. In one embodiment, a dilator may be insertedto the point of contact with the cannula, so as to perform bluntdissection of the tissue, prior to use of the grabber, hooker or puller.In some embodiments, the hooker, grabber or puller can be used to pullan implant through a hole in the spinous process after making a hole inthe spinous process, such as by using a combination bone clamp and bonepunch as described below.

The combination bone clamp and bone punch is then used to make a hole inthe spinous process suitable to receive the spinous process anchordescribed in FIGS. 25A and 25B. The bone clamp and bone punch arereleased and the surgical instrument of FIG. 29 removed. The spinousprocess anchor is inserted into the created hole in the spinous process.The implant is passed around the spaced apart uprights and tensionedusing a hemostat or other clamping instrument. The implant is fixed inposition either with a clamp such as that shown in FIG. 18A, FIG. 20A orFIG. 27, a knot tying the implant to the anchor, sutures fixing theimplant to itself, or a staple fixing the implant to itself. Thesurgical sites can be closed in the usual manner.

An alternative surgical technique using the surgical instrument 300 ofFIG. 29 is now described, in which a single implant from one inferiorvertebral body is passed to and partially around the spinous process ofthe superior vertebral body and to the inferior vertebral body on theopposite side. The implant is flexible and capable of being placed intension. Again, a midline incision may be made, progressing down to thelevel of the spinous process of the superior vertebral body. Thesurgical instrument may be clamped onto the sides of the spinous processof the superior vertebral body. An incision may be made aligned with thehole 297 on one arm of the instrument. A reduced size dilator andcannula may be assembled and introduced through the hole 297 in theinstrument to bluntly dissect down to the point of fixation on theinferior vertebral body. In one embodiment, the dilator may betemporarily removed from the cannula to incise the fascial layer. Thefascia may then be incised and the dilator reassembled to the cannula.The assembly is advanced to the points of fixation on the inferiorvertebral body. The dilator is withdrawn, leaving the cannula.

The anchor for fixation to the inferior vertebral body is assembled toan implant, or preferably comes preassembled to an implant. The anchoris put on the inserter. The inserter is passed through the cannula andused to fix the anchor to a first location on an inferior vertebralbody. This may be done unilaterally.

A grabber, hooker or puller is then introduced through the hole 296 onone arm of the surgical instrument of FIG. 29 and advanced laterallytoward the implant. In one embodiment, an additional skin incision maybe made for the grabber, hooker or puller. When the grabber, hooker orpuller contacts the cannula, the cannula is retracted until it clearsthe grabber, hooker or puller. The grabber, hooker or puller is thenfurther advanced to capture the implant. Once the implant is captured,the grabber, hooker or puller is retracted to bring the implant to thespinous process of the superior vertebral body. In one embodiment, adilator may be inserted to the point of contact with the cannula, so asto perform blunt dissection of the tissue, prior to use of the grabber,hooker or puller. In some embodiments, the hooker, grabber or puller canbe used to pull an implant through a hole in the spinous process aftermaking a hole in the spinous process, such as by using a combinationbone clamp and bone punch as described below.

The combination bone clamp and bone punch is then used to make a hole inthe spinous process. One skilled in the art will appreciate that inother embodiments, a hole in the spinous process can be made prior tofixation of an anchor and implant to the inferior vertebral body. Thebone clamp and bone punch are released and the surgical instrument ofFIG. 29 removed.

The implant is then fixed to the spinous process by passing the implantthrough the created hole in the spinous process, along the side of thespinous process, looping under the spinous process, along the side ofthe spinous process and back through the created hole. In an alternativeembodiment, the implant passes under the spinous process, through thecreated hole in the spinous process and under the spinous process again.In another embodiment, the implant passes over the spinous process,through the created hole in the spinous process and then over thespinous process again.

Optionally, after fixing the implant to the spinous process, thesurgical instrument of FIG. 29 can be reapplied and its alignmentchecked with the initial incision prior to fixation of the implant to asecond location on the inferior vertebral body.

A second incision (on the opposite side) is made for inferior vertebralbody fixation aligned with the hole 297 of the instrument. An assembledcannula and reduced size dilator is advanced in the manner previouslydescribed to the point of fixation. The dilator can then be removed.

A grabber, hooker or puller is then introduced through the hole 296 ofthe instrument arm opposite the second incision to engage the implant,and then be advanced to the cannula. An alternative hooker is introducedthrough the cannula and advanced to the point of fixation. The cannulais withdrawn completely. The grabber, hooker or puller is advanced topass beyond the alternative hooker. The alternative hooker is thenwithdrawn until it captures the implant. The grabber, hooker or pulleris retracted. A combination tamp/inserter cannula is introduced throughthe hole 297 and advanced to the implant. As the combinationtamp/inserter cannula is advanced, the alternative hooker is retracted,thus tensioning the implant. The combination tamp/inserter cannula isadvanced to the point of fixation. A screw is then inserted through thetamp/inserter cannula and fixed through the implant into the bone. Thecombination tamp/inserter cannula is removed. The implant is cut intotwo pieces between the screw fixation and the site of connection to thealternative hooker. The alternative hooker is removed (with theunsecured piece of implant) and the surgical sites closed in the usualmanner.

There are a variety of alternative surgical methods that could be doneto treat a spinal level by fixing the superior vertebral body to theinferior vertebral body using the implants, instruments and methods ofthe current application. These include fixation of the implant to thesuperior vertebral body and then passing it bilaterally to the inferiorvertebral body. Additionally, optional additional steps could beperformed to enhance fixation of the implant. For example, oneadditional step would be to use an implant with some porosity (such as apolymeric fabric) and to abrade the periosteum and bone surfaces wherethere is implant contact. The abrasions could be done with a variety ofburrs or files. With abrasion, bleeding bone can be exposed and thusbiological ingrowth into the implant may be possible. This biologicalingrowth can enhance the fixation of the implant.

It is conceived that the implants, hardware, instruments and methods ofthe current application could be used on their own. It is also conceivedthat they could be used in addition to other methods of treatment.Specifically, the current application could be used in combination withdiscectomy. This would result in removal of the chemical and physicalimpact of the herniated nucleus, while providing torsional reinforcementto prevent abnormal torsional kinematics. Also, the current applicationcan be used to supplement the use of a spinal artificial disc. Inpatients receiving artificial discs, a large amount of the annulus isremoved, thus destabilizing the spine torsionally. This is supported bythe significant percentage of patients who have facet pain followingplacement of an artificial disc.

The current application can also be used in combination with a plug orpatch to repair the annulus. There are annular repair products thatattempt to fix tears in the annulus by applying a patch or similarproduct to the site of the tear. Anulex ™ is one such company attemptingto develop this technology. In its product, a patch is sutured to theannulus. However, this is very difficult to perform and maintain, forwhen a spinal level experiences significant torsion, it is likely thatthe sutures will be unable to maintain fixation. In contrast, thecurrent application can used as described and augmented with a simpleporous plug of polymeric material, preferably one that is resorbable, tofill the hole and provide a scaffold for cells to heal the tear. In thisinstance, it might be advantageous to expose bleeding bone adjacent tothe plug to provide a larger source of cells and thereby stimulatehealing. Alternatively, the current application can be used with aproduct such as Anulex's which allows for fixation in addition to ascaffolding. The use of the current application would reduce the load onthe sutures in the Anulex product, thus increasing the potential forrepair.

The implants, hardware, instruments and methods of the currentapplication can also be used to treat multiple levels in a singlesurgical procedure. In addition, the implants, hardware, instruments andmethods of the current application could also be used to providemultidirectional stability to the spine for multilevel treatment. Thatis, instead of treating a single level, multiple levels could be treatedsimultaneously. To provide multilevel treatment, a preferred method oftreating the levels would be to install hardware to the vertebral bodybelow the lowest disc level to be treated (as described in thisapplication) and above the highest disc level to be treated (asdescribed in this application). Treatment in this manner may requirethat the implants no longer be aligned with the disc space. However,there are some advantages to this approach:

-   -   The line of action of the implants would be posterior to the        pedicle fixation that is commonly used, resulting in less force        to resist the moments applied to the spine and thus reducing the        risk of hardware loosening found in existing pedicle screw based        systems.    -   The surgery would be percutaneous thus reducing the surgical        trauma.    -   The triangular fixation resulting from bilateral fixation to the        inferior vertebral body and unilateral fixation to the superior        vertebral body would provide multidirectional stability in a way        not found in common pedicle screw constructs.        Additional Embodiments

Additional systems, methods and apparatuses related to providingtorsional stabilization to a spinal motion segment are discussed below.

Suture as a Stabilizing Implant

As described above, various stabilizing implants (such as those shown inFIGS. 4 through 8) may be placed in the spine, often in a generallytransverse manner, to provide torsional stabilization to a spinal motionsegment. According to one embodiment, the stabilizing implant may becomprised of wires or cables made of a metal, a metal alloy (such asnitinol), a mono or multifilament polymeric material, or combinationsthereof. In a preferred embodiment, the stabilizing implant is comprisedof one or more sutures placed in tension between multiple locationsalong the spine to limit axial torsion in one or more directions. Theamount of tension in one or more sutures may vary between 5 and 200 N,more preferably between 10 and 150 N. In some embodiments, the suturesmay be used on their own as a stabilizing implant, while in otherembodiments, the sutures are used as a stabilizing implant in additionto other implants.

Stabilizing implants may be fixed to various locations of the spine byusing one or more anchoring devices. These anchoring devices may includethe anchors shown in FIGS. 9 through 12, including one or more staples,threaded bone anchors, offset anchors, as well as various other anchorsand combinations thereof. In some embodiments, one or more suturinganchors (as shown in FIG. 44) may also be used.

FIG. 44 illustrates a suture anchor 511 according to one embodiment thatincludes a threaded anchoring portion 515, a suture eye 521, and areceiving hole 530. The suture anchor 511 may serve to anchor an endpoint of one or more sutures 575 that enter through the receiving hole530. The suture anchor 511 may be comprised of various materials,including but not limited to stainless steel, titanium, titanium alloy,nitinol, composites (such as combinations of TCP/PLGA), polymericmaterials such as PEEK, polyglycolic or polylactic acid polymers, andcombinations thereof.

The suture eye 521 may be of varying configurations and geometries, andmay be used to hold one or more pieces of suture 575. In one embodiment,one or more pieces of suture may be looped through the eye 521.Additionally, the eye 521 may also hold a knot of one or more sutures575. In another embodiment, the suture anchor 511 may be a knotlesssystem such that there is no need to loop a suture around an eye portionof a suture anchor. One preferred embodiment of a suture and anchorcombination uses a single suture that is attached to the anchor in themidst of the suture, resulting in two ends of a single suture for use asthe stabilizing implant. This may be achieved by passing the suturethrough an eye 521 in the anchor, or by knotting the suture to itselfafter passing through an eye 521. This preferred embodiment in that itenables use with an endobutton (shown in FIG. 46) to tension thestabilizing implant by tying one end of the suture to the other.

One embodiment of the present application may use one or more suturinganchors 511 (as shown in FIG. 44) to torsionally stabilize a spinalmotion segment by placing in tension one or more sutures 575 between aninferior vertebrae and a superior vertebrae. The stabilizing implant mayinclude sutures 575 that are preloaded and fixed to one or more anchors521. In another embodiment, one or more suturing anchors 511 may be usedin conjunction with an endobutton to tension one or more sutures betweenadjacent vertebrae to resist axial torsion.

In embodiments that are comprised of one or more sutures, the suturesmay be absorbable and made, for example, of a biodegradable polymericfiber. Alternatively, the sutures may be non-biodegradable and made of amaterial such as polypropylene, polyester or polyethylene. One of skillin the art will appreciate that various sutures may be used as astabilizing implant and the choice of materials is not limited to thosematerials mentioned above. Furthermore, the stabilizing implant may useone or more sutures that may be braided or unbraided. In one embodiment,a suture used as a stabilizing implant is constructed of a monofilamentpolymer chain having a braided jacket.

As shown in FIG. 44, the anchoring portion 515 of the suture anchor 511may be externally threaded to facilitate insertion of the suture anchorinto the bone. In one embodiment, the suture anchor 511 may be insertedinto a pre-drilled hole of a bone. In another embodiment, the sutureanchor 511 may be self-tapping by using the threaded anchoring portion515. Regardless of the type of anchor used, one or more instruments maybe used to facilitate placement of the anchor in a desired location ofthe bone.

FIG. 45A illustrates a side view of an anchor driver 501 according toone embodiment that may be used to facilitate and drive an anchor into abone. The anchor driver 501 includes a handle end 505 and a driving end508. The anchor driver 501 may be generally cylindrical in shape, and asshown in FIG. 45A, the handle end 505 may have a greater circumferencethan the driving end 508. The handle end may be affixed to a handle (notshown).

FIG. 45B illustrates a cross-sectional top view of the anchor driver ofFIG. 45A. The driving end 508 of the anchor driver includes a protrusion509 capable of making contact with an anchor head. In some embodiments,the protrusion 509 (which is also shown prominently in the exploded sideview of the tip of the anchor head in FIG. 45C) may shapely fit into ahole in the anchor head to engage the tip of the anchor driver with thesuture anchor. When the anchor driver and anchor head are engaged, theanchor driver may then be used to drive the anchor into a position inthe bone.

FIG. 46 illustrates one embodiment of an endobutton 621 having holes635. In an embodiment utilizing sutures as the stabilizing implant, oneor more sutures connected to suturing anchors may be threaded throughholes 635 of the endobutton. The endobutton 621 may then be advancedinto contact with a spinous process of a vertebrae. The sutures may thenbe knotted to each other or the endobutton 621, resulting in tension inthe sutures to limit axial torsion. In one embodiment, the endobutton621 and sutures may be used to attach various types of soft tissue tothe spinous process, including allograft, autograft, or xenografttissue.

To facilitate torsional stability between adjacent vertebrae, one ormore instruments may be used. In some embodiments, a multi-functionalinstrument such as any one of shown in FIGS. 29-32D can be used toattach one or more implants between adjacent vertebrae.

Methods are described below using a multi-functional instrument and astabilizing implant utilizing sutures according to one embodiment. Whilethe methods described are applied unilaterally to a single side of thespine, in other embodiments, a method of stabilization is appliedbilaterally. Whether a stabilizing implant is applied unilaterally orbilaterally may depend on the treatment desired and the location of thetreatment area of the patient. For example, for herniated nucleuspulposus (slipped disk) patients who have a tear in the annulus thatdetrimentally permits nucleus material to escape from the disc space, aunilateral system may be used to augment muscle that may be weakenedonly on the side of the herniation. For other types of patients seekingdifferent treatments, a bilateral system may be more appropriate.

One of skill in the art will appreciate that the methods described belowusing an implant comprising sutures are only a few of many methods inwhich a multi-functional instrument may be used to resist axial torsion.While the methods described use sutures in tension to provide torsionalstabilization, one of skill in the art will appreciate that sutures arenot mandatory, and other implants with or without sutures may also beused with the multi-functional instrument. Moreover, those skilled inthe art will appreciate that the steps need not be performed in theexact order as described and may be performed in various orders toachieve similar results.

A method using the multi-functional instrument 300 of FIG. 29 will nowbe described with accompanying illustrations in FIGS. 47A-47J:

-   -   1. A clamping mechanism of instrument 300 is used to clamp to        the spinous process 290 of a superior vertebral body as shown in        FIG. 47A. The clamping mechanism may access the spinous process        through an incision made over the spinous process. With the        clamping mechanism clamped to the spinous process 290, the arms        293, 295 of the instrument 300 will be positioned over the skin        of the patient.    -   2. Using hole 297 of the instrument 300 as a guide, a guide        drill may be guided to create a hole in the spinous process 290        of the superior vertebral body as shown in FIG. 47B.    -   3. After creating a hole in the spinous process 290, a fixation        device and suture implant can be guided using hole 296 to a        location 291 of an inferior vertebral body as shown in FIG. 47C.        In the illustrated embodiment the location 291 is the pedicle.        The fixation device and suture implant can then be attached to a        location 291 on the inferior vertebral body as shown in FIG.        47D.    -   4. After fixing the fixation device and implant to the inferior        vertebral body at 291, a pulling instrument (such as a grabber,        hooker or puller) can be passed through the hole 297 of the        multi-functional instrument, and through the hole created in the        spinous process 290, as shown in FIG. 47E. In other embodiments,        the grabber, puller or hooker need not go through the hole in        the spinous process, but rather, can go below or along side of        the spinous process to pull an implant.    -   5. The pulling instrument can be used to pull the suture implant        through the hole in the spinous process 290 as shown in FIG.        47F.    -   6. Once the suture implant has been pulled through the hole in        the spinous process, the clamping instrument may be removed,        leaving the suture implant fixed at a location 291 of the        inferior vertebral body and through the spinous process 290 as        shown in FIG. 47G.    -   7. An endobutton 622 (such as that shown in FIG. 46B) can then        be provided. The suture implant can then be threaded through the        holes of the endobutton 622 as shown in FIG. 47H.    -   8. The endobutton 622 and thread can then be advanced down the        implant until the endobutton 622 is in contact with the side of        the spinous process as shown in FIG. 47I.    -   9. After advancing the endobutton 622 to the spinous process,        the implant may be placed in tension and a tie knot may be made        using the two ends of the suture implant as shown in FIG. 47J.        One method of placing the suture implant in tension is by        applying a tensioner, which is commonly used in sports medicine        applications. In other embodiments, hand tension can also be        used to snug the knot against the endobutton 622.

As a result of the method above, torsional stabilization is provided ina unilateral manner using a suture implant and endobutton. In otherembodiments, torsional stabilization may be applied bilaterally byapplying the same method to the opposite side of the spinous process.

An alternative method using the multi-functional instrument 708 of FIG.32A is described below. The steps described below may also beimplemented with the methods previously described.

-   -   1. A patient is positioned so that the anterior-posterior axis        of a targeted disc space is oriented vertically. This alignment        is optional; however, in some patients, it may be much easier to        perform a surgery according to this alignment.    -   2. An incision is made over the spinous process of the superior        vertebral body. The depth of the incision will vary depending on        the area of the body to be treated.    -   3. The instrument 708 may then be used to attach to the spinous        process by using a clamping mechanism. In one embodiment, tines        715 may be used to clamp on the sides of the spinous process.        Alternatively, a bone clamp may be used that serves as a        combination clamp and bone punch such that a hole may be created        in the spinous process.    -   4. The instrument 708 may then be held in a vertical position,        matching the anterior-posterior axis of the disc space.    -   5. A skin incision may then be made using one of the anchor        holes 732 as a guide. The anchor holes 732 are oriented to align        with a series of locations that may be desirable locations for        fixing one or more fixation devices, such as screws, staples or        soft tissue anchors.    -   6. Through the skin incision, a needle, dilator or cannula as        described above may be used to create a working channel from the        incision to the desired location for fixing one or more fixation        devices.    -   7. Using the cannula described above, a soft tissue anchor        preloaded with one or more sutures as described herein may be        implanted.    -   8. A drill or bone awl may be introduced through one of the        passing holes 740 and may be used to create a hole in the        spinous process adjacent to the tines 715.    -   9. A hooker, grabber or puller as described above may be        inserted through the passing hole 740, through the created hole        in the spinous process and across to the cannula containing the        soft tissue anchor.    -   10. The cannula and inserter may then be retracted.    -   11. The hooker, grabber or puller may then be advanced to        capture the sutures. In one embodiment, the sutures may be        tensioned to enhance capture.    -   12. The hooker, grabber or puller, along with the captured        sutures, may then be retracted through the created hole in the        spinous process and out of the patient's body completely along        with the sutures.    -   13. The instrument 708 may then be removed.    -   14. The sutures may then be threaded through holes in an        endobutton, such as described above, and the endobutton advanced        in contact with the spinous process.    -   15. Knots may then be used to tighten the sutures to the        endobutton, resulting in adequate tension in the sutures to        limit axial torsion. In a preferred embodiment, two ends of a        single suture are used as the stabilizing implant and are tied        to each other after passing through separate holes in an        endobutton. Although in one embodiment, axial torsion is limited        in a single direction, it may be possible to limit axial torsion        in multiple directions using sutures of different orientation.    -   16. The incisions may then be closed in a normal fashion.        Soft Tissue Graft and Fabric Implants

Various stabilizing implants may be used as described above. In oneembodiment, the stabilizing implants may be comprised of soft tissuegrafts, including autograft, allograft, xenograft or combinationsthereof. Examples of tissue to be used includes fascia latae,semitendonosis and gracilis tendons, hamstring tendon, patellar tendon,quadriceps tendon, Achilles tendon, small intestine submucosa (SIS) andskin, including processed xenografts such as the Zimmer® Collagen RepairPatch and DePuy® Restore Biologic Implant. In an alternative embodiment,the implants may be comprised of one or more fabrics. These implants maybe placed proximate to various locations along the spine, and may befixed into position by using screws, staples, anchors or other fixationdevices as described herein. Depending on the fixation device, one ormore sutures may be attached to one end of the fixation device (such asa screw or staple) to maintain an implant in tension.

Numerous methods exist that allow one skilled in the art to position oneor more implants between different locations of the same vertebrae or inbetween different locations of adjacent vertebrae. In one embodiment, astabilizing implant may be pre-assembled to a fixation device, such asan anchor, before being used in a surgery. The term “pre-assembled”refers to an implant that has been assembled to a fixation device beforethe implant is placed into actual use, and preassembly can take place,for example, on a back table in the operating suite or in an outsidefacility.

FIG. 50 illustrates one embodiment in which a suture anchor 511 with oneor more sutures 575 is attached to one end of an implant 540, while oneor more sutures 590 are attached to an opposite end of the implant 540.In a preferred embodiment, the implant comprises a soft tissue graft ora fabric. In one embodiment, and with reference to FIG. 50, a method offixation is provided in which a suture anchor 511 is pre-assembled toone end of a stabilizing implant 540 before the stabilizing implant 540is inserted into the body of the patient. One or more sutures 575 of thesuture anchor 511 are used to sew, knot and/or tie the suture anchor 511to the stabilizing implant 540 prior to insertion into the patient.Besides the sutures 575 of the suture anchor 511, one or more additionalsutures 590 may be pre-attached to the opposite end of the stabilizingimplant 540. When the suture anchor 511 having sutures 575 attached toone end of the stabilizing implant 540 is inserted into a desiredlocation in the bone, in one embodiment, the sutures 590 at the oppositeend of the implant 540 may be placed in tension, for example, byhooking, grabbing or pulling the sutures 590. These sutures 590 may beused to help maintain tension in the implant while the sutures arethemselves maintained in tension, for example, when a hooker, grabber orpuller is used to capture the sutures 590. Alternatively, the implantmay be placed in tension when a hooker, grabber or puller is used tocapture the stabilizing implant 540. In yet another embodiment, thesutures 590 that are used to maintain tension in the implant may also beused to fix the implant to an endobutton 621 as shown in FIG. 46.

In accordance with systems, methods and apparatuses of anotherembodiment, a hole 542 may be created in a stabilizing implant 541, suchas a fabric or soft tissue graft, to pass a headed screw through thehole as shown in FIG. 51. The head of the screw may be used to hold thestabilizing implant down to the bone. In one embodiment in which theimplant is a fabric, a hole may be used with or without reinforcement.The term “reinforcement” is used to describe using a metal or polymericgrommet, or using sewing, knitting or embroidery techniques to increasethe thread density in the area surrounding the hole. In an alternativeembodiment in which the implant is a soft tissue graft, a hole may becreated by looping the graft back on itself and suturing across one ormore legs of the graft. At the end opposite the hole, one or moresutures 590 may be provided to maintain an implant in tension asdescribed above. In another embodiment, the sutures 590 that are used tomaintain tension in the implant may also be used to fix the implant toan endobutton 621 as shown in FIG. 46.

Measuring Devices and Methods

Methods and apparatuses are described that relate to measuring astabilizing implant, such as a soft tissue graft or fabric. In oneembodiment, the stabilizing implant may be measured and in some cases,modified, after being inserted into the body. In a preferred embodiment,the stabilizing implant will be measured to be an appropriate lengthbefore insertion into the body. Techniques for measuring the stabilizingimplants can be incorporated into any of the methods described herein.

In one embodiment, the sizing of an implant may be based on theinstruments used to insert the implants. Under this approach, the sizeof the implants may be based on the dimensions of the instrument that isused. In one embodiment, for example, in which a multi-functionalinstrument as shown in FIG. 32A is used to position implants fortorsional stabilization, the position and orientation of the anchor hole732 relative to the tines 715 and the passing hole 740 generally specifythe length of the stabilizing implant. Once the instrument is selected(for example, based on the location of the spinous process and theanchor holes), in one embodiment, the stabilizing implant may beselected from a group of implants sized to match the selected instrumentappropriately. Under this approach, one or more multi-functionalinstruments may be provided to cover the variations in size expected inthe patient population.

In another embodiment, one skilled in the art may use a measuringinstrument 802 as shown in two different views in FIGS. 48A and 48B.FIG. 48A illustrates a side view of a measuring instrument assembly 802comprised of a measurement instrument frame 822 and a measurementfilament 830. FIG. 48B illustrates a front view of the measurementinstrument assembly 802, in which the measurement instrument includes acut out portion 850 that allows a hooker, grabber or puller to capturethe measurement filament 830 when the instrument is assembled and inuse.

FIG. 49A illustrates one embodiment of the measurement instrument frame822 according to one embodiment. With respect to an assembly 802 havingtwo components, the frame 822 and the filament 830, the frame 822 may bethe stationary portion. The frame may have a cut out portion 850 thatpermits a hooker, grabber or puller from capturing a filament 830located in the frame 822. Moreover, in another embodiment, the frame mayinclude a post that spans the inner diameter of the frame. The postprovides a means for attachment of the filament.

FIG. 49B illustrates one embodiment of a measuring filament 830according to one embodiment. The filament 830 may be comprised of asuture, wire, cable or other flexible material. In some embodiments, thefilament 830 is comprised of a biocompatible polymer or metal. In apreferred embodiment, the filament is comprised of a flexible materialcapable of being placed in tension in order to provide a propermeasurement of a suitable implant.

In one embodiment, and as shown in FIG. 49B, the filament 830 may be anunmarked suture, wire, cable or other flexible material. In someembodiments, the filament may include a series of marked parallel linesthat extend around the shape of the filament. The lines could be createdby printing, engraving, laser marking or etching. Such lines maycorrespond with length, and would aid in the proper measuring of animplant. In some embodiments, it is possible that the filament include aseries of grooves or indentations, which may also serve to assist inproper measuring of an implant. In one embodiment, the filament 830 isread within the body, such as through an opening in the patient's body,with or without an instrument. For example, one may be able to view afilament that is marked with actual numbers while the filament is in usewithin a patient's body without using any additional instruments.Alternatively, one may view the filament 830 after it is removed from apatient's body, for example, by using a chemical compound such asmethylene blue with the filament to indicate areas in which themeasurement instrument was placed in the body. Besides these methods,other methods of reading the measurement filament 830 may also beemployed, and one skilled in the art will not be limited to anyparticular technique.

The frame 822 and filament 830 may assume a number of shapes. In oneembodiment, the filament has one end shaped like a toroid (as shown inFIG. 49B) to allow for rotational movement of the filament about thepost within the frame. This rotational movement may be important whenthe filament 830 is assembled into the frame 822, as the rotation may beimportant for measuring the length of the stabilizing implant and it isexpected that an implant may rotate similarly when tensioned.

In some embodiments, filament 830 may be suitable for permanent use witha frame 822, and thus may be suitable for reuse. Under theseembodiments, the filament 830 may be marked, either by writing orindentation, so that it could be reused multiple times. In otherembodiments, the filament 830 may be made completely disposable, whichwould allow the filament 830 to be cut as desired to assist in measuringan implant. The cut filament 830, once removed from a patient, may bemeasured using a standard measuring means such as a ruler to assist infinding an implant of appropriate size. In an alternative embodiment, ameasurement assembly 802 can be designed such that a frame 822 isreusable.

A method is now provided for using the multi-functional instrument 708in FIG. 32A and the measuring instrument 802 having a measuring filament830 and measuring frame 850 shown in FIGS. 48A and 48B to measure andinstall an implant. One of skill in the art will appreciate that themethod described is only one of many methods in which the measuringinstrument assembly 802 can be used to measure an implant. Moreover,those skilled in the art will appreciate that the steps need not beperformed in the exact order as described, and therefore, may beperformed in various orders to achieve similar results.

The method is described as follows:

-   -   1. A patient is positioned so that the anterior-posterior axis        of a targeted disc space is oriented vertically. This alignment        is optional; however, in some patients, it may be much easier to        perform a surgery according to this alignment.    -   2. An incision is made over the spinous process of the superior        vertebral body. The depth of the incision will vary depending on        the area of the body to be treated.    -   3. A multifunctional instrument 708 may then be used to attach        to the spinous process by using a clamping mechanism. In one        embodiment, tines 715 may be used to clamp on the sides of the        spinous process. Alternatively, a bone clamp may be used that        serves as a combination clamp and bone punch such that a hole        may be created in the spinous process.    -   4. The instrument 708 may then be held in a vertical position,        matching the anterior-posterior axis of the disc space.    -   5. A skin incision may then be made using one of the anchor        holes 732 as a guide. The anchor holes 732 are oriented to align        with a series of locations that may be desirable locations for        fixing one or more fixation devices, such as screws, staples or        soft tissue anchors.    -   6. Through the skin incision, a needle, dilator or cannula as        described above may be used to create a working channel from the        incision to the desired location for fixing one or more fixation        devices.    -   7. A drill or bone awl may be introduced through one of the        passing holes 740 and may be used to create a hole in the        spinous process adjacent to the tines 715.    -   8. A measuring instrument 802 with measurement filament 830 may        then be inserted into the cannula and held to the bone.    -   9. A hooker, grabber or puller is inserted through the passing        hole 740, through the created hole in the spinous process, and        across to the cannula containing the measuring instrument 802.    -   10. The cannula may then be partially retracted.    -   11. The hooker, grabber or puller may then be advanced to        capture the measurement filament.    -   12. The hooker, grabber or puller (with the captured measurement        filament) may then be retracted through the created hole in the        spinous process, and out of the patient's body along with the        measurement filament 830.    -   13. The measurement filament 830 may be tensioned and read or        cut to length for measurement outside of the patient's body.    -   14. The measuring instrument 802 (including filament 830) may        then be removed.    -   15. A stabilizing implant of an appropriate length may then be        selected from a plurality of implants based on the measurement        provided by the measuring instrument 802. In an alternative        embodiment, if an implant of appropriate size is not available,        a stabilizing implant of an appropriate length may be prepared.    -   16. The dilator and cannula may then be reinserted through the        anchor hole and advanced to the targeted position. The dilator        may then be removed.    -   17. The stabilizing implant and inserter may then be inserted        through the cannula and fixed to the lower vertebral body.    -   18. A hooker, grabber or puller may then be inserted through the        passing hole, through the drilled hole in the spinous process,        and across to the cannula containing the stabilizing implant.    -   19. The cannula and inserter may then be retracted.    -   20. The hooker, grabber or puller may then be advanced to        capture the stabilizing implant and associated sutures.    -   21. The hooker, grabber or puller (with the captured sutures)        may then be retracted through the created hole in the spinous        process, and out of the patient's body along with the sutures.    -   22. The instrument 708 may then be removed.    -   23. One or more sutures may then be threaded through holes in an        endobutton 621 and the endobutton 621 may be advanced into        contact with the spinous process.    -   24. One or more knots may be used to tighten the sutures to the        endobutton 621, resulting in adequate tension in the sutures to        limit axial torsion in one or more directions. In a preferred        embodiment, two ends of a single suture 590 are tied to each        other after passing through separate holes in an endobutton.    -   25. Incisions are closed in the normal fashion.        Suture Anchor and Suture Plug

With the advent of stronger and more durable suture materials, there isthe potential to have sutures function mechanically for a long period oftime. One current limitation of suture longevity is the connectionbetween the suture and its associated hardware, such as soft tissueanchors. A publication by Bardana et al. entitled “The Effect of SutureAnchor Design and Orientation on Suture Abrasion: An In Vitro Study,”Arthroscopy, 2003, 19(3), 274-281, highlights some concerns. In thearticle, the authors found that the eyelet geometry and surface finishof the suture anchors had a significant effect on suture abrasion.Abrasion of the suture was also impacted by the direction of pull on thesuture.

An improved suture anchor and associated devices, such as suture plugs,that result in reduced (minimal to zero) abrasion on sutures to preventthe repeated replacement of sutures used in patients is desired.Embodiments of improved suture anchors and suture plugs are describedbelow. The suture anchor and suture plug may be used on their own, incombination or in addition to the systems, methods and apparatusesdescribed herein for providing torsional stabilization.

This application describes novel suture anchors that will reduceabrasion associated with motion between the suture anchor and suture andthereby enhance the mechanical longevity of the suture assembly. Thedesign of the improved suture anchor may have slight variationsdepending on the line of pull of the suture with respect to the longaxis of the anchor. In this application, two embodiments are described,one in which a suture is at a generally 90 degree orientation with along axis of an anchor (shown in FIG. 52) and another in which the lineof pull of a suture is generally aligned with the long axis of theanchor (shown in FIG. 59). A novel suture plug that can be fixed intothe spinous process of a spinal vertebral body is also described. Inaddition, systems, methods and apparatuses related to surgicalinstruments that allow for proper alignment between the suture anchor,the suture plug and the spinous process are also provided.

FIG. 52 shows a side view of one embodiment of a suture anchor for usewith a suture that is to be pulled along a line generally 90 degrees tothe long axis of the anchor. According to the embodiment, one or moresutures may be pulled transversely to the long axis of the anchor. Thesuture anchor 1002 has a standard means for attaching to bone, in thiscase, a self-tapping thread 1001. The head of the suture anchor 1002 isseparated from the thread by a collar 1003 which may be cylindrical inshape, or may have any other suitable shape. The head 1008 of the sutureanchor extends above the collar 1003, and within the head 1008 of thesuture anchor is an eyelet hole 1004 defining an opening extendingtransversely to the long axis of the anchor. When viewed from above asshown in FIG. 54, the head 1008 of the anchor may in one embodiment havegenerally a figure-eight shape.

In addition to these features, the suture anchor provides an anchor head1008 having a novel geometry that mitigates abrasion to a suture when inuse. In the illustrated embodiment, the eyelet hole 1004 transitionssmoothly into and is defined between two posts 1005 shown in FIG. 53.FIG. 53 illustrates the transverse cross-section of the head of thesuture anchor at the center of the eyelet as measured along long axis ofthe anchor, wherein the eyelet diameter is at its largest. The posts1005 at this central eyelet location in one embodiment each has a roundcross-section, and when extending away from the central eyelet locationalong the long axis of the anchor, either toward the thread 1001 ortoward the top of the head of the anchor, each of the rounded postsgradually increase in diameter. As the diameter of the rounded postsincreases in diameter both toward the top and bottom ends of the anchor,the center points defining the diameter of the posts moves graduallyaway from the outer edge of the head of the anchor toward the otherpost. Eventually, at the top and bottom of the head of the anchor, thetwo posts merge together, thereby closing off the eyelet.

The outer surfaces of the posts 1005 as they vary in diameter adjacentto the eyelet may be considered to be lofted surfaces 1006, which mayalso be seen as one side of each of the posts 1005. One or more suturesare capable of being pulled in tension while resting on the loftedsurfaces 1006 with minimal risk of abrasion. The head 1008 of the sutureanchor 1002 also provides indentations 1007, as best seen in FIG. 54,which assist in the placement of one or more sutures in the head of thesuture anchor via use of an inserter as described below. As shown inFIG. 52, the head 1008 of the suture anchor also comprises a top surface1008A and base surface 1008B of the anchor head that enclose the eyelethole 1004 from top and bottom, with the base surface 1008B being theportion that rests on collar 1003. These surfaces of anchor head 1008may be considered to be the portions where the posts 1005 merge asdescribed above. The surface of the suture head also helps to containthe sutures in the track created by the surface. Depending on the sizeof the eyelet, the suture anchor shown in FIG. 52 may contain andreceive one suture or multiple sutures, such as two, three, four, fiveor more.

In one embodiment, one or more sutures may pass through the eyelet 1004such that when tensioned, the sutures pull around one or more posts1005. In the illustrated embodiment, the cross-section of the post 1005is circular (as shown in FIG. 53), while in other embodiments, thecross-section may be elliptical, oval or other generally roundgeometries. There are no sharp edges that can abrade the sutures whenthe suture slides relative to the post through the eyelet. Loftedsurfaces 1006, seen in FIG. 52, may help to ensure that there is asmooth transition between the eyelet 1004 and the edge of the head. Insome embodiments, these “lofted” surfaces refer to smooth, roundedsurfaces that form one side of the post 1005 and form the materialbetween the eyelet hole 1004 and the edge of the head of the sutureanchor 1002. In the illustrated embodiment, the lofted surfaces 1006form a smooth surface from the base of the anchor head 1008 to the topof the post 1005. In one embodiment, the lofted surfaces 1006 form anarcuate seat or groove upon which one or more tensioned sutures may reston and be cupped with minimal risk of abrasion. In some embodiments, thelofted surfaces 1006 may form two or more arcuate seats or grooves thatallow multiple sutures in tension to be cupped with minimal risk ofabrasion.

FIG. 53 shows a cross-sectional top view of the suture anchor of FIG.52. FIG. 53 illustrates how the suture anchor head 1008 is shapedsimilar to a figure eight. While the suture anchor head 1008 is shapedlike a figure eight for purposes of this embodiment, one skilled in theart will appreciate that the suture anchor head may be of other shapesincluding a rectangle (as shown in FIG. 59). The shape of the surfacescan be designed to mate with a portion of an inserter device as shown inFIG. 55. As shown in FIG. 53, the post 1005 is circular and formed bythe contour of the lofted surfaces 1006. In this embodiment, thecross-section of the lofted surfaces 1006 form generally round surfaceareas from the base surface of the anchor head 1008 to the post 1005. Inone embodiment, the area of the generally round surface areas decreasesin size from the base surface of the anchor head 1008 to around themiddle of the post 1005 and increase in size from around the middle ofthe post 1005 to the top surface of the anchor head 1008, to form asmooth arcuate seat or groove where one or more sutures in tension canbe placed. While the illustrated embodiment shows the cross-section ofthe post 1005 and its lofted surfaces 1006 as being circular, thecross-section may vary in shape (e.g., they may be elliptical) so longas the lofted surfaces 1006 form a smooth, edgeless section that reducesthe risk of suture abrasion.

FIG. 54 shows a top view of the suture anchor of FIG. 52. FIG. 54illustrates geometrical portions 1008 for mating with the suture anchorinserter as described below and indentations 1007 which can be used toprovide an opening for the one or more sutures to pass through whenusing a suture anchor inserter. Also shown in FIG. 54 is the top of thecollar 1003, over which the suture anchor head rests.

In a preferred embodiment, the surfaces 1006 of the suture anchor head1002 are produced to a high surface finish, such as would be appropriatefor use on the metal articulation of total joint replacements (between0.1 to 0.5 microns (Ra)). At the same time, the geometrical portion 1008that mates with the inserter (seen in FIGS. 52 and 54), may be moreroughly finished without impacting the articulation between the anchorand the suture.

FIGS. 55 and 56 illustrate a side view and cross-sectional viewrespectively of an anchor inserter 1041 according to one embodiment. Theanchor inserter 1041 has an end 1042 which connects to a suture anchor,and a second end 1043 which can affix to a handle (not shown). A centralhole 1051 penetrates through the inserter which allows one or moresutures to pass through while the inserter is connected to a sutureanchor. In one embodiment, the anchor inserter 1041 has an oblong cavity1052 designed to slidably mate with the top of the suture anchor at theanchor head 1008 at surfaces adjacent to the lofted surface 1006 of thesuture anchor. In other embodiments, such as those that include sutureanchor heads having different geometries, the anchor inserter may have acavity of a different shape, such as rectangular. Indentations 1007allow sutures loaded on the suture anchor to be torqued and extendedthrough the cavity 1052 of the anchor inserter. This is because there isminimal to zero contact between the inserter 1041 and the anchor in theregion of the indentations 1007, which permits the suture to be pulledwithin the central hole 1051 of the inserter 1041 while the inserter isbeing used to place the suture anchor loaded with the sutures in acertain location. In addition, the inserter and suture anchor contactare designed to avoid the surfaces 1006 of the suture anchor so as toavoid marring the surface.

An alternative embodiment of a suture anchor 1060 is shown in FIGS.57-59, in which the line of pull of the suture is intended to begenerally along the long axis of the suture anchor. The suture anchor1060 has a means for attaching to bone, in this case, a self-tappingthread 1061. The head of the suture 1062 is separated from the thread bya collar 1063 as described above. Within the head of the suture anchoris an eyelet hole 1064 that extends transverse to the long axis of theanchor. In addition to these features, the suture anchor provides asuture head having a novel geometry that allows for reduced abrasionwhen in contact with one or more sutures. The eyelet hole 1064transitions smoothly into a post 1065 (shown in FIG. 58) having one sidewith lofted surfaces 1066. Unlike the embodiment of FIG. 52, wherein theposts 1005 are located to the transverse sides of the eyelet 1004, inFIG. 59, the post 1065 is located above and toward the top of the eyelet1064. One or more sutures can pass through the eyelet and whentensioned, can pull around the post 1065 and rest on or be cupped inportions of the lofted surfaces 1066 with minimal risk of abrasion. Inone embodiment, the cross section of the post is circular, while inother embodiments it may be elliptical, oval or other generally roundgeometries. There are no sharp edges that can abrade the sutures whenthe suture slides relative to the post. Lofted surfaces 1066, seen inFIG. 57, may help ensure that there is a smooth transition between theeyelet 1064 and the edge of the head. The surface 1066 also tends tocontain the sutures in the track created by the surface. The loftedsurfaces 1066 are formed by the post 1065 gradually increasing indiameter from the center of the eyelet transversely towards the edges ofthe eyelet. As the diameter increases away from the center of theeyelet, the center of radius for the post shifts downward toward thethreads of the anchor.

FIG. 58 is a cross-sectional side view of the suture anchor of FIG. 57.From this view, the post 1065 and the lofted surfaces which surround thepost can be easily seen. As in FIG. 53, the cross-section of the loftedsurfaces form circles from the base of the anchor head to the top of thepost 1065. The cross-sectional area of the circles may vary in size,such that the area decreases in size from one transverse side of thescrew to the middle of the eyelet at the long-axis of the suture anchor,and increases in size from the middle of the eyelet at the long-axis ofthe suture anchor to the other transverse side of the screw. While theillustrated embodiment shows the cross-section of the post 1065 and itslofted surfaces 1066 as being circular, the cross-section may vary inshape (e.g., it may be elliptical) so long as the lofted surfaces 1006form a smooth, edgeless section that reduces the risk of sutureabrasion.

FIG. 59 is a top view of the suture anchor of FIG. 57. The top viewillustrates the suture head 1062 having portions that surround theeyelet hole 1064 and the post 1065, and which rests on collar 1063. Thesuture head 1062 comprises a rectangular top with which an anchorinserter may geometrically mate. The lofted surfaces 1066 have sweeping,curved features that extend from the top of the anchor head 1062downwardly toward the eyelet 1064.

For suture anchor 1062, a modification of the anchor inserter 1041 maybe used, with an alternative cavity to receive the anchor. In oneembodiment, the cavity may receive the suture anchor 1060 via a slidingfit with the surfaces 1068. In some embodiments, there is no contactbetween the inserter and the anchor in the region of the indentations1067, permitting the suture to be pulled within the central hole of theinserter and avoid contact between the inserter and the surfaces 1066.Like the suture anchor in FIG. 52, the suture anchor 1060 may containone suture or multiple sutures, such as two, three, four, five or evenmore.

In a preferred embodiment, the surfaces 1066 of the head 1062 areproduced to a high surface finish, such as appropriate for use on themetal articulation of total joint replacements (between 0.1 to 0.5microns (Ra)). At the same time, the geometrical portion 1068 that mateswith the inserter can be more roughly finished without impacting thearticulation between the anchor and the suture.

The suture anchors of the present application can be composed of avariety of biocompatible materials, including metals (notably titaniumalloys, nitinol alloys, Co—Cr alloys, stainless steels), polymers (PEEK,UHMWPE, Acetal, polylactic acid), composites (such as PEEK reinforcedCarbon Fiber, hydroxyapatite-polyhydroxybutyrate composite materialtrademarked Biosteon®, and tricalcium phosphate-polylactic acidcomposites), allograft or xenograft bone.

While described as a suture anchor, the suture anchors of the presentapplication could be used with a variety of relatively compliantstructures besides or in addition to sutures, such as monofilament ormultifilament wire, cable, weaves, braids or knits, including thosemanufactured of biocompatible metals, polymers or composites, includingboth resorbable and nonresorbable materials, and assemblies of the abovestructures.

FIGS. 60-63 illustrate a novel suture plug 1101 for fixing one or moresutures in tension with a bony component, such as the spinous process.The suture plug 1101 has a leading end 1102 and a trailing end 1103. Insome embodiments, one or both ends 1102 and 1103 may be circular inshape, thus making the outer surface 1104 of the suture plug a conicsection. The leading end 1102 is generally smaller in diameter than thetrailing end 1103 as shown in FIG. 60. Within the suture plug is acentral cavity 1105. The central cavity is bridged by a strut 1106 atthe trailing end 1103 of the suture plug. Two openings 1107 are formedfrom the combination of the central cavity 1105 and the strut 1106. Thecorners 1108 of the strut 1106 are radiused so as to remove sharpcorners that may result in abrasion or fretting of the suture.

Methods are now described using the suture plug according to oneembodiment. A machined cavity is formed within a bone, using drills,reamers and similar instruments, some of which may be contoured to matchthe outer surface 1104 of the suture plug. One or more ends of a suture,or other similarly compliant structure, may be pulled through themachined cavity in the bone. The suture ends are threaded through thecentral cavity 1105 of the suture plug 1101, from leading end 1102towards trailing end 1103. If using two or more suture ends, ends arepassed on opposite sides of the strut 1106. If using one suture end, itis passed fully around the strut and then out through the trailing end.The suture plug 1101 may then advance along the sutures until it ispressed into the machined cavity in the bone. The suture is tightened,perhaps with the aid of a tensioner. The suture ends are then tied off,preferably using knots. Alternatively, the suture ends could be crimped,welded or otherwise joined so as to fix the ends of the suture withrespect to the suture plug.

In a preferred embodiment, the central cavity 1105 of the suture plug1101 is sized to have contact with one or more sutures only on the strut1106. That is, the suture plug may be preferably oriented in either acollinear alignment with the long axis of a suture anchor such as thatshown in FIG. 57. In an alternative embodiment, the suture plug isoriented in a perpendicular alignment with the long axis of a sutureanchor such as that shown in FIG. 52 and aligned with the eyelet 1004 ofthe anchor. In these orientations, the sutures will be aligned with thecentral axis of the suture plug, avoiding misalignment that could causecontact between the sutures and the suture plug that may result in wear,fretting or fatigue of either the suture or the suture plug and apotential diminution of the mechanical life of the system.

The suture plug could be formed of a variety of metal, polymeric ornatural materials, as well as composites of these materials. Theseinclude permanent materials such as titanium alloys, nitinol alloys,Co—Cr alloys, stainless steels, PEEK, PEEK reinforced carbon fiber,UHMWPE, nylon and acetal. Alternatively, the suture plug could be formedof resorbable or partially resorbable materials such as polylactic acid(PLA), polyglycolic acid (PGA), autograft, allograft or xenograft bone,as well as composites such as hydroxyapatite-polyhydroxybutyratecomposite material trademarked Biosteon®, tricalciumphosphate-polylactic acid composites or biocomposites that are composedof part natural materials and either mineral or polymer, such as Plexur™marketed by Osteotech, Inc.

The suture anchors, anchor inserters and suture plugs of the presentapplication could have use in a variety of orthopedic surgicalapplications, such as shoulder, knee or hip applications. Additionally,the suture anchors, anchor inserters and suture plugs of the presentapplication could be used as elements in addition to those systems,methods and apparatuses described above that are related to torsionallyresistive spinal implantation. For example, in one embodiment, thesuture anchor of FIGS. 52-54 may be used, so that the pull of thesuture, when directed towards the spinous process of the superiorvertebral body, would be along a line generally 90 degrees with respectto the axis of the anchor. The suture plug would be used to fix the plugto the spinous process of the superior vertebral body.

FIG. 64A illustrates one embodiment of a suture anchor 1110 and a sutureplug 1112 including a single suture 1114 according to one embodiment.FIG. 64B illustrates the same suture anchor 1110 and suture plug 1112 ofFIG. 63A shown from a top view. The suture anchor 1110 shown in FIGS.64A and 64B is similar to the suture anchor shown in FIG. 52, as itallows for a line of pull of a suture 1114 that is perpendicular to thelong axis of the suture anchor 1110. As shown in FIG. 64A, the singlesuture 1114 wraps around a single post on only one side of the sutureanchor 1110 and enters through an opening of the suture plug 1112 suchthat there is little to no surface area that may abrade the suture 1114.In another embodiment, one or more sutures in addition to suture 1114may be wrapped around the same post of suture anchor 1110. In yetanother embodiment, one or more sutures may be wrapped around adifferent post of the suture anchor 1110 if needed. These sutures wouldhave a pull in the opposite direction of the suture 1114, and may alsobe connected to a suture plug.

Accordingly, a method is presented below that applies both themulti-functional instrument 1201 shown in FIG. 32C and a novel sutureanchor and suture plug to provide torsional stabilization. One of skillin the art will appreciate that the method described below is only oneof many methods in which the instrument 1201 may be used to limit axialtorsion. Moreover, those skilled in the art will appreciate that thesteps need not be performed in the exact order as described and may beperformed in various orders to achieve similar results.

The method is described as follows:

-   -   1. A patient is positioned so that the anterior-posterior axis        of a targeted disc space is oriented vertically. This alignment        is optional; however, in some patients, it may be much easier to        perform a surgery according to this alignment.    -   2. An incision is made over the spinous process of the superior        vertebral body. The depth of the incision will vary depending on        the area of the body to be treated.    -   3. The instrument 1201 may then be used to attach to the spinous        process by using a clamping mechanism. In one embodiment, tines        1203 may be used to clamp on the sides of the spinous process.        Alternatively, a bone clamp may be used that serves as a        combination clamp and bone punch such that a hole may be created        in the spinous process.    -   4. The instrument 1201 may then be held in a vertical position,        matching the anterior-posterior axis of the disc space.    -   5. The skin is retracted laterally and a cavity is created in        the spinous process. In a preferred embodiment, the tools used        to make the cavity may be guided by the combination passing and        anchor hole 1205 so as to ensure alignment of the cavity. The        cavity may match the outer surface 1104 of the suture plug 1101.    -   6. Following creation of the cavity in the spinous process, a        needle, dilator or cannula may be used to create a working        channel from the incision to the desired location for fixing one        or more suture anchors, such as 1060.    -   7. Using the cannula described above, a soft tissue anchor        preloaded with one or more sutures, such as described above, may        be implanted using an anchor inserter.    -   8. The anchor inserter and cannula is retracted out through the        cavity in spinous process and out of the patient along with the        free end(s) of the suture.    -   9. The instrument 1201 may then be removed.    -   10. The sutures may then be threaded through holes in a suture        plug, such as described above, and the suture plug advanced in        contact with the cavity created in the spinous process.    -   11. Knots may then be used to tighten the sutures to the suture        plug, resulting in adequate tension in the sutures to limit        axial torsion. In a preferred embodiment, two ends of a single        suture are used as the stabilizing implant and are tied to each        other after passing through the suture plug. Although in one        embodiment, axial torsion is limited in a single direction, it        may be possible to limit axial torsion in multiple directions        using sutures of different orientation and by proper positioning        of the combination passing and anchor holes so that the sutures        and suture plugs do not interfere with each other.    -   12. The incisions may then be closed in a normal fashion.

While this invention has been particularly shown and described withreference to embodiments thereof, it will be understood by those skilledin the art that various changes in form and details may be made thereinwithout departing from the scope of the invention. For all of theembodiments described above, the steps of the methods need not beperformed sequentially.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the scope or spirit of the invention. Thus, it isintended that the present invention cover modifications and variationsof this invention.

I claim:
 1. A method for providing torsional stabilization to a spine,comprising: extending an implant between a first vertebral body and asecond vertebral body, the implant being attached to a fixation devicerigidly fixed to a spinous process of the second vertebral body andextending laterally outwardly to attach to a location on the firstvertebral body without penetrating a facet of the first vertebral body,wherein the fixation device does not engage the spinous process of thefirst vertebral body; wherein the implant is fixed at a first fixationpoint to the first vertebral body and at a second fixation point to thesecond vertebral body, wherein the first and second fixation points andthe implant lie substantially within the same plane parallel with a discspace between the first and second vertebral bodies, such that relativemovement between the first fixation point and the second fixation pointaway from one another is resisted during axial rotation of the spine bytensioning the implant without contacting or fixing any apparatus to thespinous process of the first vertebral body.
 2. The method of claim 1,wherein the implant is attached to a pedicle of the first vertebralbody.
 3. The method of claim 1, wherein the implant is attached to amamillary process of the first vertebral body.
 4. The method of claim 1,wherein the implant is attached to the location on the first vertebralbody by a screw, staple, soft tissue anchor, suture anchor or adhesive.5. The method of claim 1, wherein the implant comprises a polymericsurgical fabric, autograft soft tissue or allograft soft tissue.
 6. Themethod of claim 1, wherein the implant comprises one or more sutures. 7.The method of claim 1, wherein the implant passes through a hole in thespinous process of the second vertebral body.
 8. The method of claim 1,wherein the fixation device comprises a turnbuckle, an outrigger, athimble, an endobutton or a suture plug.
 9. The method of claim 1,wherein the implant is prevented from translating with respect to thefixation device at least during axial rotation of the spine in which thefirst fixation point and the second fixation point are moved away fromone another.
 10. The method of claim 1, further comprising using ananchor driver to secure an anchor to the location on the first vertebralbody.
 11. The method of claim 1, wherein relative movement between thefirst fixation point and the second fixation point away from one anotheris resisted unilaterally during axial rotation of the spine bytensioning the implant on a first lateral side of the spine withoutcontacting or fixing any apparatus to the first vertebral body on asecond lateral side of the spine opposite the first side.
 12. The methodof claim 1, wherein the first fixation point is located on a firstvertebral body in the lumbar spine in a region from the pediclesuperiorly and medially onto the mammillary process.
 13. The method ofclaim 1, wherein the first fixation point is located on a firstvertebral body at the sacrum.
 14. The method of claim 1, wherein thefirst fixation point is located on a first vertebral body in thecervical spine on the lateral aspect of the superior articular process.15. A method for providing torsional stabilization to a spine,comprising: creating a hole through a spinous process of a superiorvertebral body; attaching a suture to a location on an inferiorvertebral body without penetrating a facet of the inferior vertebralbody; extending the suture from the inferior vertebral body to thespinous process of the superior vertebral body without passing throughthe facet of the inferior vertebral body, the suture extendingsubstantially within a plane parallel with a disc space between thesuperior and inferior vertebral bodies; and securing the suture to thespinous process of the superior vertebral body via an endobutton securedadjacent to the hole in the spinous process, the suture being tensionedwithin said plane; wherein after securing the suture to the spinousprocess, the entire length of the suture between the inferior vertebralbody and the spinous process lies substantially within the planeparallel with the disc space between the superior and inferior vertebralbodies.
 16. The method of claim 15, wherein the suture is attached tothe location on the inferior vertebral body with a suture anchor. 17.The method of claim 16, wherein the suture anchor is preloaded with oneor more sutures.
 18. The method of claim 15, wherein the location on theinferior vertebral body comprises a pedicle of the inferior vertebralbody.
 19. The method of claim 15, wherein the suture is attached to thelocation on the inferior vertebral body before creating the hole throughthe spinous process.
 20. The method of claim 15, further comprisingusing an instrument to pull the suture through the hole in the spinousprocess prior to securing the suture to the spinous process of thesuperior vertebral body via the endobutton.
 21. The method of claim 15,further comprising threading the suture through one or more holes in theendobutton.
 22. The method of claim 15, further comprising applying aknot to the suture.
 23. The method of claim 15, further comprising usinga tensioner to place the suture in tension.
 24. A method for providingtorsional stabilization to a spine, comprising: extending a suturebetween an inferior vertebral body and a superior vertebral body, thesuture being attached at a first fixation point to a first fixationdevice rigidly fixed to a spinous process of the superior vertebral bodyand at a second fixation point to a second fixation device rigidly fixedto a location on the inferior vertebral body located laterally outwardfrom the first fixation point, the suture being placed under tensionbetween the first fixation point and the second fixation point, whereinthe first fixation device does not engage the spinous process of theinferior vertebral body; wherein relative movement between the inferiorvertebral body and the superior vertebral body is resisted unilaterallyduring axial rotation of the spine by tensioning the suture on a firstlateral side of the spine between the first fixation point and thesecond fixation point without contacting or fixing any apparatus to theinferior vertebral body on a second lateral side of the spine oppositethe first lateral side, without contacting or fixing any apparatus tothe spinous process of the inferior vertebral body, and withoutextending the suture through the facet of the inferior vertebral body;and wherein the first and second fixation points and the entire lengthof the suture being tensioned between the first and second fixationpoints lie within a plane parallel with the disc space between thesuperior and inferior vertebral bodies.